Fix image rendering after clear cache

[bmarty]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

Ensure that after a clear cache from the application settings, the Matrix images (room and user avatar, images in timeline, etc.) are correctly rendered.

Also doing some cleanup, rework and add a unit test (see per commit)

Motivation and context

Fix existing bug.

Screenshots / GIFs

Tests

• Start the app and navigate to the room list. There are some room avatars in the list.
• From the developer setting, clear the cache

Previous: the room avatars are not rendered, the initial avatars are diaplyed
Now: the room avatars are loaded correctly

Tested devices

• Physical
• Emulator
• OS version(s):

Checklist

• Changes have been tested on an Android device or Android emulator with API 23
• 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 includes a new file under ./changelog.d. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#changelog
• Pull request includes screenshots or videos if containing UI changes
• Pull request includes a sign off
• You've made a self review of your PR

[github-actions]

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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

Attention: Patch coverage is 70.58824% with 5 lines in your changes missing coverage. Please review.

Project coverage is 75.98%. Comparing base (cb14be2) to head (40594b7).

Files	Patch %	Lines
...ent/android/appnav/root/RootNavStateFlowFactory.kt	0.00%	2 Missing ⚠️
.../libraries/matrix/ui/media/ImageLoaderFactories.kt	0.00%	2 Missing ⚠️
...essionstorage/test/observer/FakeSessionObserver.kt	85.71%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3082      +/-   ##
===========================================
+ Coverage    75.94%   75.98%   +0.04%     
===========================================
  Files         1633     1634       +1     
  Lines        38589    38595       +6     
  Branches      7460     7460              
===========================================
+ Hits         29305    29326      +21     
+ Misses        5394     5379      -15     
  Partials      3890     3890              

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[jmartinesp]

LGTM, thanks!