Refactor exam_users_edit.html to improve formatting and maintainability of the user addition panel

generic/templates/generic/exam_users_edit.html

@@ -39,7 +39,7 @@
 </div>
 
         <!-- Collapsible panel for adding arbitrary users (collapsed by default) -->
-        <div class="mt-3">
+<div class="mt-3">
     <p>
         <a class="btn btn-sm btn-link" data-bs-toggle="collapse" href="#add-arbitrary-users-collapse" role="button" aria-expanded="false" aria-controls="add-arbitrary-users-collapse">Add arbitrary users</a>
     </p>
@@ -52,7 +52,7 @@
             </div>
         </div>
     </div>
-        </div>
+</div>
 
 <script>
     // Mirror the HTMX-enabled behavior used for CID users.