mailbox backend: don't show identity delete action on mailbox identity

views/backend/mailbox.njk

@@ -28,6 +28,7 @@
                         <td>{{ identity.id }}</td>
                         <td>{{ identity.email }}</td>
                         <td class="actions">
+                            {% if mailbox.name != identity.email %}
                                 <form action="{{ route('backend-delete-mail-identity') }}" method="POST">
                                     <input type="hidden" name="id" value="{{ identity.id }}">
 
@@ -38,6 +39,7 @@
 
                                     {{ macros.csrf(getCsrfToken) }}
                                 </form>
+                            {% endif %}
                         </td>
                     </tr>
                 {% endfor %}