workspacesView: Remove obsolete cleanup

Since commit a9f11b1f5a, we no longer set up a later on
parent-set, so there's nothing to clean up.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2626>

js/ui/workspacesView.js

@@ -854,16 +854,6 @@ class WorkspacesDisplay extends St.Widget {
         this._leavingOverview = false;
 
         this._gestureActive = false; // touch(pad) gestures
-
-        this.connect('destroy', this._onDestroy.bind(this));
-    }
-
-    _onDestroy() {
-        if (this._parentSetLater) {
-            const laters = global.compositor.get_laters();
-            laters.remove(this._parentSetLater);
-            this._parentSetLater = 0;
-        }
     }
 
     _windowDragBegin() {