backoffice: make users and settings accessible when there are no users (#6726)

wcs/qommon/admin/menu.py

@@ -182,6 +182,8 @@ def error_page(section, error):
 
 def is_accessible(key):
     if not get_request().user:
+        if get_publisher().user_class.count() == 0:
+            return key in ('settings', 'users')
         return False
 
     user_roles = set(get_request().user.roles or [])