edgeDragAction: Change edge trigger threshold to AFTER

For all instances of this gesture, we want this gesture to
activate after some distance, not to eat button presses/releases
right away.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2304>

js/ui/edgeDragAction.js

@@ -19,6 +19,7 @@ var EdgeDragAction = GObject.registerClass({
         this._side = side;
         this._allowedModes = allowedModes;
         this.set_n_touch_points(1);
+        this.set_threshold_trigger_edge(Clutter.GestureTriggerEdge.AFTER);
 
         global.display.connect('grab-op-begin', () => this.cancel());
     }