CustomPip: fix next loosing video

When running in custom pip, video playback is not in the
videoPlayerActivity. When starting next media, it checks if there is a
video playing, and if (appIsStarted()) which returns false when customPip
is running and the VideoPlayerActivity has been killed.

Because of this, when playing the following media in a playqueue with
custom pip, there no vout. To fix this, this adds a check to
service.isInPiPMode before removing video.

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

@@ -494,7 +494,8 @@ class PlaylistManager(val service: PlaybackService) : MediaWrapperList.EventList
         }
 
         val mw = mediaList.getMedia(index) ?: return
-        if (mw.type == MediaWrapper.TYPE_VIDEO && !isAppStarted()) videoBackground = true
+        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()
         setRepeatTypeFromSettings()
         if (!videoBackground && isVideoPlaying) mw.addFlags(MediaWrapper.MEDIA_VIDEO)