[AND-462] (compose): Replace VideoView with ExoPlayer + PlayerView.

[VelikovPetar]

🎯 Goal

Introduces media3.exoplayer to the compose SDK to improve playing of video (and audio) attachments.

🛠 Implementation details

• Adds androidx.media3:media3-exoplayer and androidx.media3:media3-ui dependencies. (There is also a compose artefact (media3-ui-compose), however it is in very early development, and doesn't provide all the options like the media3-ui does (fast forward/backward, speed controls, progress indicator...))
• Rework the MediaGalleryVideoPage to use PlayerView + ExoPlayer (instead of VideoView)
• Rework the MediaAttachmentActivity to user PlayerView + ExoPlayer (instead of VideoView)

🎨 UI Changes

Add relevant screenshots

Scenario	Before	After
Video (MediaGalleryVideoPage)	before.mp4	after.mp4
Audio (MediaPreviewActivity)	before-audio.mp4	after-audio.mp4

🧪 Testing

1. Open compose sample app
2. Open channel with Video attachments
3. Play the video attachment (the performance should be much better than previously)

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	3.16 MB	3.16 MB	0.00 MB	🟢
stream-chat-android-offline	3.38 MB	3.38 MB	0.00 MB	🟢
stream-chat-android-ui-components	7.89 MB	7.89 MB	0.00 MB	🟢
stream-chat-android-compose	9.94 MB	12.38 MB	2.44 MB	🔴

[sonarqubecloud]

Quality Gate failed

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud