Group: Fix advanced search when adding user to class - refs BT#22195

Author: AngelFQC

main/admin/add_users_to_usergroup.php

@@ -326,6 +326,7 @@ function showLastTenUsers() {
 
 $filterData = [];
 if ($searchForm->validate()) {
+    $showAllStudentByDefault = true;
     $filterData = $searchForm->getSubmitValues();
 
     foreach ($filters as $filter) {