FFs can now be toggled in release builds too

[jmartinesp]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

• Removed StaticFeatureFlagProvider.
• Always provide PreferencesFeatureFlagProvider.
• For the default values of feature flags, use a lambda with a BuildMeta parameter so we can customize the return value based on its data.

Motivation and context

Fixes #3073.

Tests

• In a release build, access the hidden developer settings.
• Toggle one of the many options.
• Check the change took effect.

Tested devices

• Physical
• Emulator
• OS version(s): 14

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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[codecov]

Codecov Report

Attention: Patch coverage is 80.76923% with 5 lines in your changes missing coverage. Please review.

Project coverage is 76.00%. Comparing base (0c543ab) to head (a4872dc).
Report is 84 commits behind head on develop.

❗ Current head a4872dc differs from pull request most recent head d7a2340

Please upload reports for the commit d7a2340 to get more accurate results.

Files	Patch %	Lines
...featureflag/impl/PreferencesFeatureFlagProvider.kt	0.00%	2 Missing ⚠️
...libraries/featureflag/impl/di/FeatureFlagModule.kt	0.00%	2 Missing ⚠️
.../android/libraries/featureflag/api/FeatureFlags.kt	93.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3101      +/-   ##
===========================================
+ Coverage    75.96%   76.00%   +0.03%     
===========================================
  Files         1636     1635       -1     
  Lines        38617    38600      -17     
  Branches      7463     7461       -2     
===========================================
+ Hits         29335    29337       +2     
+ Misses        5393     5373      -20     
- Partials      3889     3890       +1     

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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