[FIX] Fix Invalid title when adding a user to a newly created user group in action.tpl

• Fix invalid title when adding a user to a newly created user group by accessing the first element of the target array that contains the message, for task https://avan.tech/item104243-Fix-Invalid-title-when-adding-a-user-to-a-newly-created-user-group?from=Add-a-task-confirmation-message