Reader: Migrate seen posts from Redux to TS Query

[mehmoodak]

Fixes READ-561

Proposed Changes

Migrate seen-posts Redux store to TanStack query.

Why are these changes being made?

Improves consistency and DevEx.

Testing Instructions

• Go to any A8C or P2 feeds.
• Verify seen post functionality:
  • Opening the post should mark it as read.
  • Open the ellipsis menu on Post card and mark the post as read or unread.
  • Mark all posts as read.
  • From post detail view use eye icon to toggle the status of read / unread.

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• For UI changes, have you tested the affected components in dark mode?
• Have you tested accessibility for your changes? Ensure the feature remains usable with various user agents (e.g., browsers), interfaces (e.g., keyboard navigation), and assistive technologies (e.g., screen readers) (PCYsg-S3g-p2).
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184124

Jetpack Cloud Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184124&env=jetpack

Automattic for Agencies Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184124&env=a8c-for-agencies

Dashboard Live (dotcom) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184124&env=dashboard

Dashboard Live (A4A) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184124&env=dashboard-a4a

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• agents-manager
• help-center
• notifications
• odyssey-stats
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug READ-561/refactor-seen-posts-code-from-Redux-to-Tanstack-Query on your sandbox.