Refactor: replace client-side event filtering for public rooms with SDK

[jmartinesp]

Content

Replace FilterPublicEmptyDayPostProcessor and FilterPublicMembershipChangesPostProcessor with some simple SDK timeline filters.

Motivation and context

Replace and simplify #6360

Tests

The app should behave just as it did: join and leave events and display name / avatar url changes in publicly accessible, non-encrypted rooms should be hidden. Since the filter happens in the SDK, day dividers for empty days should also be removed automatically.

Tested devices

• Physical
• Emulator
• OS version(s): 15

Checklist

• I am aware of the etiquette.
• This PR was made with the help of AI:
  • Yes. In this case, please request a review by Copilot.
  • No.
• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly defines what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[github-actions]

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[jmartinesp]

Flaky test spotted?

> Task :features:linknewdevice:impl:testDebugUnitTest

ScanQrCodeViewTest > try again button clicked - emits the expected event FAILED
    java.lang.IllegalArgumentException at ScanQrCodeViewTest.kt:83

[bmarty]

LGTM, thanks!

[codecov]

Codecov Report

❌ Patch coverage is 0% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.61%. Comparing base (a3a0fda) to head (4656e01).
⚠️ Report is 4 commits behind head on develop.

Files with missing lines	Patch %	Lines
...ies/matrix/impl/room/TimelineEventFilterFactory.kt	0.00%	11 Missing ⚠️
...roid/libraries/matrix/impl/room/RustRoomFactory.kt	0.00%	9 Missing ⚠️
...droid/libraries/matrix/impl/room/JoinedRustRoom.kt	0.00%	5 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #7025      +/-   ##
===========================================
- Coverage    80.64%   80.61%   -0.03%     
===========================================
  Files         2678     2676       -2     
  Lines        76229    76217      -12     
  Branches     10252    10249       -3     
===========================================
- Hits         61474    61444      -30     
- Misses       10824    10844      +20     
+ Partials      3931     3929       -2     

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