fix: drop empty label from network errors

[criticalAY]

Note

Assisted-By: Claude Opus 4.8 - analysing the upstream cause and testing the fix

Purpose / Description

When a sync fails with a network error (e.g. AnkiWeb is down or unreachable), the error dialog shows a dangling "Error details:" label with nothing after it. There are simply no details to show, so the bare label looks unfinished. This pr cleans that

Also i have opened an issue upstream:

• Network error message shows a dangling "Error details:" label when there are no details ankitects/anki#5117

Fixes

• Fixes Empty error should not show half a sentence #21306

Approach

• Added stripEmptyErrorDetails() in CoroutineHelpers.kt to drop that trailing label before the message is shown

How Has This Been Tested?

unit testing

Learning (optional, can help others)

Describe the research stage

Links to blog posts, patterns, libraries or addons used to solve this problem

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[david-allison]

I feel this should be fixed upstream, unless we're deviating from their behaviour.

If we still want to do it here, we should add a test which fails when upstream have fixed the issue, so we can remove the dead code

[criticalAY]

I would incline with later we can remove this once upstream actually ships it since I am not sure how long it would take

[david-allison]

I'll leave the question open for Reviewer 2.

If we are continuing, please see if you can detect when this code is no longer necessary via a test

• The code isn't executed often
• The user impact of the bug is small
• It's a fair amount of complexity to fix
• It's likely hard to determine when upstream has fixed the issue and we can remove the code

[BrayanDSO]

it's less work to send a patch to upstream then consume it here

[criticalAY]

Sure: ankitects/anki#5120

[criticalAY]

Closing in favour of the upstream fix(merged):

• fix: omit empty "Error details:" line from network errors ankitects/anki#5120