wayland: Ensure to remove destroy listener for MetaWaylandBuffer

Avoid the chance of invalid memory access by leaving the wl_listener
behind when handling the destroy notification.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2588>

src/wayland/meta-wayland-buffer.c

@@ -89,6 +89,7 @@ meta_wayland_buffer_destroy_handler (struct wl_listener *listener,
     wl_container_of (listener, buffer, destroy_listener);
 
   buffer->resource = NULL;
+  wl_list_remove (&buffer->destroy_listener.link);
   g_signal_emit (buffer, signals[RESOURCE_DESTROYED], 0);
   g_object_unref (buffer);
 }