PlayIndex: fix play-as-audio

By getting a media from the medialibrary from the the currentmedia's uri
to ensure that we have the medialibrary metadata for the file, the new
media from the same uri won't have the flags previously set, including
MEDIA_FORCE_AUDIO which start the media as audio.

To fix this, the flags from the previous mediawrapper are applied to the
new one.

Fixed a regression introduced by ea39df7bb7

application/vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt

@@ -484,6 +484,7 @@ class PlaylistManager(val service: PlaybackService) : MediaWrapperList.EventList
 
         val media = mediaList.getMedia(index) ?: return
         val mw = medialibrary.getMedia(media.uri) ?: media
+        mw.flags = media.flags
         val isInCustomPiP: Boolean = service.isInPiPMode.value ?: false
         if (mw.type == MediaWrapper.TYPE_VIDEO && !isAppStarted() && !isInCustomPiP) videoBackground = true
         val isVideoPlaying = mw.type == MediaWrapper.TYPE_VIDEO && player.isVideoPlaying()