dev/core#2601 fix joomla permission regression

This was a change we ultimately decided to, but forgot to, revert. It gave
extensions the ability to modify already-defined-permissons but
was brought out of scope of the change as it required more
consideration that simply adding the new super duper permission

In the meantime it caused a Joomla! regression
https://lab.civicrm.org/dev/core/-/issues/2601

CRM/Core/Permission/Base.php

@@ -398,10 +398,9 @@ public function getModulePermissions($module): array {
    * @return array
    *   Array of permissions, in the same format as CRM_Core_Permission::getCorePermissions().
    */
-  public function getAllModulePermissions($descriptions = FALSE, &$permissions): array {
-    $newPermissions = [];
-    CRM_Utils_Hook::permission($newPermissions, $permissions);
-    $permissions = array_merge($permissions, $newPermissions);
+  public function getAllModulePermissions($descriptions = FALSE): array {
+    $permissions = [];
+    CRM_Utils_Hook::permission($permissions);
 
     if ($descriptions) {
       foreach ($permissions as $permission => $label) {