[No QA] Remove unsafe type assertions from APITest.ts tests

[KJ21-ENG]

Explanation of Change

Removed @typescript-eslint/no-unsafe-type-assertion violations from tests/unit/APITest.ts as part of the cleanup for Expensify/App issue #94739.

What changed:

• Replaced unsafe API command assertions with typed READ_COMMANDS and WRITE_COMMANDS constants.
• Added typed helpers for API request parameters.
• Replaced the mocked Onyx type assertion with typed mock usage.
• Preserved the existing test scenarios, fixtures, and assertions.

Why this approach is safe:

• Runtime behavior and test scenarios are unchanged.
• The diff is limited to tests/unit/APITest.ts.
• All 26 focused Jest tests passed.
• Fork CI passed typecheck, lint, format, React Compiler, and Jest checks.
• The actual three-way merge with current main introduced no Knip findings.

Reviewer focus:

• Confirm that the typed API command constants preserve the existing command names and payload shapes.
• Confirm that the typed request-parameter helpers preserve existing test behavior.
• Confirm that the Onyx mock usage and test assertions remain semantically unchanged.

Safety checks:

• Focused lint passed with zero target violations.
• CI-mode lint passed and the generated TSV evidence was restored byte-for-byte.
• Focused Jest passed all 26 tests.
• Formatter, Oxfmt, React Compiler, and diff-hygiene checks passed.
• The signed publication head and current-main merge compatibility were verified.

Fixed Issues

$ #94739
PROPOSAL: #94739 (comment)

Count change

Current baseline source:

• config/eslint/eslint.seatbelt.tsv

Before:

• tests/unit/APITest.ts: 61 violations

After:

• tests/unit/APITest.ts: 0 violations

Net reduction:

• 61 fewer @typescript-eslint/no-unsafe-type-assertion violations.

TSV evidence:

• Writable lint removed the target row when the count reached zero.
• The generated TSV was restored byte-for-byte and is intentionally not included in this PR because Expensify/App post-merge automation tightens the baseline on main.

Tests

1. npm run lint -- --show-warnings tests/unit/APITest.ts

   • Focused lint passed with no target warnings.

2. CI=true npm run lint -- --no-cache --show-warnings tests/unit/APITest.ts

   • CI-mode lint passed.
   • The generated TSV reflected zero violations and was restored afterward.

3. npm run test -- tests/unit/APITest.ts

   • All 26 focused Jest tests passed.

4. Focused lint, writable lint evidence, formatter checks, React Compiler checks, and all focused Jest tests passed on the exact signed publication head.

Offline tests

Not applicable because this is a test-only type-safety cleanup with no network behavior.

QA Steps

Not applicable because production behavior and UI code are unchanged.

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I followed proper code patterns (see Reviewing the code)
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
• If new assets were added or existing ones were modified, I verified that:
  • The assets are optimized and compressed (for SVG files, run npm run compress-svg)
  • The assets load correctly across all supported platforms.
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Not applicable because there are no UI changes; this cleanup only changes a unit test.

iOS: Native

Not applicable because there are no UI changes; this cleanup only changes a unit test.

Android: Chrome

Not applicable because there are no UI changes; this cleanup only changes a unit test.

iOS: Safari

Not applicable because there are no UI changes; this cleanup only changes a unit test.

Desktop: Chrome/Safari/Firefox

Not applicable because there are no UI changes; this cleanup only changes a unit test.