first try: fix mysql problem (not all users found)

app/models/group.rb

@@ -423,7 +423,7 @@ class Group < Namespace
   def update_two_factor_requirement
     return unless saved_change_to_require_two_factor_authentication? || saved_change_to_two_factor_grace_period?
 
-    User.from_union([users_with_descendants, project_users_with_descendants]).find_each(&:update_two_factor_requirement)
+    [users_with_descendants, project_users_with_descendants].each {|set| set.find_each(&:update_two_factor_requirement)}
   end
 
   def path_changed_hook