messageTray: Drop hack to keep track of X11

This is here to cater for lost events while the pointer wanders
into untracked shell UI (thus not part of the input region under
X11). Let mutter handle this situation instead.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1556>

js/ui/messageTray.js

@@ -842,17 +842,6 @@ var MessageTray = GObject.registerClass({
             this._onStatusChanged(status);
         });
 
-        global.stage.connect('enter-event', (a, ev) => {
-            // HACK: St uses ClutterInputDevice for hover tracking, which
-            // misses relevant X11 events when untracked actors are
-            // involved (read: the notification banner in normal mode),
-            // so fix up Clutter's view of the pointer position in
-            // that case.
-            let related = ev.get_related();
-            if (!related || this.contains(related))
-                global.sync_pointer();
-        });
-
         let constraint = new Layout.MonitorConstraint({ primary: true });
         Main.layoutManager.panelBox.bind_property('visible',
                                                   constraint, 'work-area',