Fix wayland clients not deleting when they're hidden

We kept an extra reference for wayland clients and dropped it on their final
render to stop crashes.  However, if they're not on screen at the time of
their deletion this reference still needed to be dropped.

Fixes clients remaining on the deskmirror after dying on another desktop.

src/bin/e_comp_wl.c

@@ -2471,6 +2471,13 @@ _e_comp_wl_client_cb_del(void *data EINA_UNUSED, E_Client *ec)
 
    if (ec->internal_elm_win)
      evas_object_hide(ec->frame);
+
+   /* WL clients take an extra ref at startup so they don't get deleted while
+    * visible.  Since we drop that in the render loop we need to make sure
+    * it's dropped here if the client isn't going to be rendered.
+    */
+   if (!e_pixmap_is_x(ec->pixmap) && ec->hidden) e_object_unref(E_OBJECT(ec));
+
    _e_comp_wl_focus_check();
 }