clear playing cover art when shuffling

src/ui/play_queue.rs

@@ -103,7 +103,6 @@ mod imp {
     }
 }
 
-
 glib::wrapper! {
     pub struct PlayQueue(ObjectSubclass<imp::PlayQueue>)
         @extends adw::Bin, gtk::Widget,

src/ui/window.rs

@@ -385,6 +385,7 @@ mod imp {
         #[template_callback]
         async fn shuffle_all(&self) {
             self.obj().set_can_click_shuffle_all(false);
+            self.obj().set_playing_cover_art(None::<gdk::Paintable>);
 
             self.mpv.command(["stop"]).unwrap();
             self.playlist_model.remove_all();