fix: Close Applictions on Main.overview.hide()

This seems to work more correctly. It still closes on clicking an app
icon or search result, but also on "New Window", "Show Details", etc.

Fixes pop-os/beta#319.

extension.js

@@ -451,15 +451,9 @@ function gnome_40_enable() {
 
     applications.enable();
 
-    const appIcon_activate = AppDisplay.AppIcon.prototype.activate;
-    inject(AppDisplay.AppIcon.prototype, 'activate', function(button) {
-        appIcon_activate.call(this, button);
-        applications.hide();
-    });
-
-    const searchResult_activate = Search.SearchResult.prototype.activate;
-    inject(Search.SearchResult.prototype, 'activate', function() {
-        searchResult_activate.call(this);
+    const overview_hide = Main.overview.hide;
+    inject(Main.overview, 'hide', function() {
+        overview_hide.call(this);
         applications.hide();
     });
 }