Add feature flag for voice messages

[jonnyandrew]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

Add feature flag for voice messages.

Motivation and context

• [Story] Record and send a voice message element-meta#2084
• [Story] Receive and play a voice message element-meta#2083

Screenshots / GIFs

Tests

N/A

Tested devices

• Physical
• Emulator
• OS version(s): N/A

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/vector-im/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/vector-im/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

[jonnyandrew]

cc @julioromano

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[github-actions]

📱 Scan the QR code below to install the build (arm64 only) for this PR.

If you can't scan the QR code you can install the build via this link: https://i.diawi.com/MnXpVC

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (daf46d7) 58.70% compared to head (12314b3) 58.71%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1507   +/-   ##
========================================
  Coverage    58.70%   58.71%           
========================================
  Files         1133     1133           
  Lines        30300    30306    +6     
  Branches      6215     6215           
========================================
+ Hits         17789    17794    +5     
- Misses        9840     9841    +1     
  Partials      2671     2671           

Files	Coverage Δ
.../android/libraries/featureflag/api/FeatureFlags.kt	100.00% <100.00%> (ø)
...ries/featureflag/impl/StaticFeatureFlagProvider.kt	0.00% <0.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.