backoffice: fix access to ics endpoint as a backoffice URL (#20676)

wcs/backoffice/management.py

@@ -947,7 +947,7 @@ class FormPage(Directory):
             raise errors.TraversalError()
         get_response().breadcrumb.append( (component + '/', self.formdef.name) )
 
-    def check_access(self):
+    def check_access(self, api_name=None):
         session = get_session()
         user = get_request().user
         if user is None and get_publisher().user_class.count() == 0: