[5.4] PHP8.5 Deprecations (joomla#46136)

* PHP8.5 Deprecations
* Update administrator/components/com_menus/src/Model/MenuModel.php

---------

Co-authored-by: Tuan Pham Ngoc <[email protected]>

Author: dgrammatiko

administrator/components/com_menus/src/Model/MenuModel.php

@@ -364,7 +364,7 @@ public function &getModules()
         foreach ($modules as &$module) {
             $params = new Registry($module->params);
 
-            $menuType = $params->get('menutype');
+            $menuType = $params->get('menutype', '');
 
             if (!isset($result[$menuType])) {
                 $result[$menuType] = [];