UI: Set restart state when there is no media

When there is no media, set the media to the restart state.
Currently, this only affects the VLC source, as the media
source doesn't use the OBS_MEDIA_STATE_NONE, at this time.

UI/media-controls.cpp

@@ -253,6 +253,7 @@ void MediaControls::RefreshControls()
 	switch (state) {
 	case OBS_MEDIA_STATE_STOPPED:
 	case OBS_MEDIA_STATE_ENDED:
+	case OBS_MEDIA_STATE_NONE:
 		SetRestartState();
 		break;
 	case OBS_MEDIA_STATE_PLAYING: