Pass user (possibly nobody) to pundit

In some views we try to do policy validation, however we do not
require authentication, therefore no user object is avaliable to pundit
which raises an exception (look app/policies/application_policy.rb)

Fixes #7743

src/api/app/controllers/webui/webui_controller.rb

@@ -288,7 +288,7 @@ def check_ajax
   end
 
   def pundit_user
-    User.session! if User.session
+    User.possibly_nobody
   end
 
   # dialog_init is a function name called before dialog is shown