fix(player): suppress volume indicator during audio duck events (#1899)

When using AAudio output on Android, the system notifies the app to
manually handle ducking instead of silently lowering volume itself.
This caused the in-app volume indicator to pop up on every notification.

Pass showIndicator: false for duck begin/end calls so volume is adjusted
silently, consistent with other audio output modes.

lib/services/audio_session.dart

@@ -28,6 +28,7 @@ class AudioSessionHandler {
           case AudioInterruptionType.duck:
             PlPlayerController.setVolumeIfExists(
               (PlPlayerController.getVolumeIfExists() ?? 0) * 0.5,
+              showIndicator: false,
             );
             // player.setVolume(player.volume.value * 0.5);
             break;
@@ -47,6 +48,7 @@ class AudioSessionHandler {
           case AudioInterruptionType.duck:
             PlPlayerController.setVolumeIfExists(
               (PlPlayerController.getVolumeIfExists() ?? 0) * 2,
+              showIndicator: false,
             );
             // player.setVolume(player.volume.value * 2);
             break;