VLCPlaybackService: Fix wrong stream recognition

This merge request brings a fix to the wrong live stream recognition.

If the current playing media has been recognized as a live stream and it turns out to have a positive value length, the player in the control center is updated to the default player.

The playback is not interrupted anymore at the end of the media and the play/pause and previous/next interactions do not lead to the end of the playback either.

Closes #1416 (closed)