Cleanup the javascript for enabling dialog or panel links.

1) We don't need to loop over the elements to bind the event handler.
2) Just include gallery.panel.js for all the admin pages.

modules/user/helpers/user_theme.php

@@ -23,10 +23,4 @@ class user_theme_Core {
     $view->user = user::active();
     return $view->render();
   }
-
-  static function admin_head($theme) {
-    if (strpos(Router::$current_uri, "admin/users") !== false) {
-      $theme->script("gallery.panel.js");
-    }
-  }
 }