remove a dropdown-toggle icon in not-potal-page

src/server/views/widget/page_tabs.html

@@ -81,7 +81,7 @@
     {% else %}
     <li class="nav-item dropdown">
       <a
-        {% if user %} role="button" class="dropdown-toggle" data-toggle="dropdown" {% endif %}
+        {% if user %} role="button" data-toggle="dropdown" {% endif %}
         {% if not user %}
           class="dropdown-toggle dropdown-toggle-disabled"
           data-toggle="tooltip" data-placement="top" data-container="body" title="{{ t('Not available for guest') }}"