Voice message: variable play back speed (#5121)

* Implement voice message variable playback speed

* Move playback speed string to Untranslated

https://github.com/element-hq/element-x-ios/pull/5121#discussion_r2822631371

* Address review feedback for voice message playback speed

- Persist voice message playback speed as an enum in AppSettings instead of storing an index.
- Update playback speed cycling to derive from enum allCases and safely fall back to `.default` if the stored value cannot be resolved.
- Apply runtime speed updates in AudioPlayer only when the player is in the `.playing` state.
- Keep MediaPlayerProviderTests formatting/indentation style intact while retaining mock playback speed setup.
- Regenerate preview snapshots for:
  - PlaybackSpeedButton
  - VoiceMessageRoomPlaybackView
  - VoiceMessageRoomTimelineView

* Move VoiceMessagePlaybackSpeed outside AppSettings, remove speedRatio

* Stabilize PlaybackSpeedButton width

* Sync voice-message speed label

- Add voiceMessagePlaybackSpeed to TimelineViewState and bind it from appSettings.$voiceMessagePlaybackSpeed.
- Pass that timeline-level speed into VoiceMessageRoomPlaybackView and use it for PlaybackSpeedButton, so labels update consistently across items.
- Use @EnvironmentObject in VoiceMessageRoomTimelineContent so the view re-renders when timeline context state changes.
- In WaveformInteractionModifier, add .allowsHitTesting(showCursor) to the cursor interaction view so hidden pre-playback cursor hit area does not steal taps from the speed button.

ElementX/Sources/Services/Audio/Player/AudioPlayerProtocol.swift

@@ -40,15 +40,17 @@ protocol AudioPlayerProtocol: AnyObject {
     var currentTime: TimeInterval { get }
     var playbackURL: URL? { get }
     var state: MediaPlayerState { get }
-    
+    var playbackSpeed: Float { get }
+
     var actions: AnyPublisher<AudioPlayerAction, Never> { get }
-    
+
     func load(sourceURL: URL, playbackURL: URL, autoplay: Bool)
     func reset()
     func play()
     func pause()
     func stop()
     func seek(to progress: Double) async
+    func setPlaybackSpeed(_ speed: Float)
 }
 
 // sourcery: AutoMockable