[Web] hide auth heading for external managed users

data/web/templates/user/tab-user-auth.twig

@@ -99,10 +99,10 @@
             </div>
           </div>
 
+          {% if mailboxdata.authsource == "mailcow" %}
           <legend class="mt-4">{{ lang.user.authentication }}</legend>
           <hr>
           {# Password Change #}
-          {% if mailboxdata.authsource == "mailcow" %}
           <div class="row">
             <div class="col-12 col-md-3 d-flex"></div>
             <div class="col-12 col-md-9 d-flex flex-wrap">