fix: add AddNewRole button handler in options.js

The Add New Role button was not working because the AddNewRole
JavaScript function was missing from options.js. Added the handler
function following the same pattern as AddNewUser.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

web/skins/classic/views/js/options.js

@@ -48,6 +48,12 @@ function AddNewUser(el) {
   window.location.assign(url);
 }
 
+// Manage the Add New Role button
+function AddNewRole(el) {
+  url = el.getAttribute('data-url');
+  window.location.assign(url);
+}
+
 function initPage() {
   const NewStorageBtn = $j('#NewStorageBtn');
   const NewServerBtn = $j('#NewServerBtn');