Patch function "Display Name" into admin page

core/admin/mailu/ui/templates/sidebar.html

@@ -5,7 +5,11 @@
       <div class="div-circle elevation-2"><i class="fa fa-user text-lg text-dark"></i></div>
     </div>
     <div class="info">
+      {%- if current_user.displayed_name %}
+      <a href="{{ url_for('.user_settings') }}" class="d-block">{{ current_user.displayed_name }}</a>
+      {% else %}
       <a href="{{ url_for('.user_settings') }}" class="d-block">{{ current_user }}</a>
+      {%- endif %}
     </div>
   </div>
   {%- endif %}