macosx: update play and playback mode status on startup

Because the playback might have been started before the interface
registeres its callbacks, set the state manually.

close #14046

modules/gui/macosx/intf.m

@@ -798,6 +798,13 @@ static VLCMain *_o_sharedMainInstance = nil;
     [o_mainwindow updateTimeSlider];
     [o_mainwindow updateVolumeSlider];
 
+    /* Hack: Playlist is started before the interface.
+     * Thus, call additional updaters as we might miss these events if posted before
+     * the callbacks are registered.
+     */
+    [self PlaylistItemChanged];
+    [self playbackModeUpdated];
+
     // respect playlist-autostart
     // note that PLAYLIST_PLAY will not stop any playback if already started
     playlist_t * p_playlist = pl_Get(VLCIntf);