refactor: use SSoT for playback speed

shared/src/commonMain/kotlin/fr/ajaury/gwenedeg/player/ui/viewmodel/PlayerViewModel.kt

@@ -62,7 +62,6 @@ class PlayerViewModel(
             if (alreadyLoadedRecord != null) {
                 logger.debug("Record $recordId already loaded")
                 playbackRepository.load(record = alreadyLoadedRecord)
-                applyCurrentSpeed()
                 return@launch
             }
 
@@ -73,16 +72,10 @@ class PlayerViewModel(
             }
 
             playbackRepository.load(record = loadedRecord)
-            applyCurrentSpeed()
             record.value = loadedRecord
         }
     }
 
-    private suspend fun applyCurrentSpeed() {
-        val playbackPreferences = preferencesRepository.playbackPreferences.firstOrNull() ?: return
-        playbackRepository.setSpeed(playbackPreferences.speed)
-    }
-
     fun performMainPlayAction() {
         when (uiState.value.playerState.playbackState) {
             PlaybackState.PLAYING -> playbackRepository.pause()
@@ -113,9 +106,9 @@ class PlayerViewModel(
             PlaybackPreferences.MIN_SPEED,
             PlaybackPreferences.MAX_SPEED,
         )
+
         viewModelScope.launch {
             preferencesRepository.setPlaybackSpeed(clampedSpeed)
-            playbackRepository.setSpeed(clampedSpeed)
         }
     }