[REF] 8.0 mgmtsystem_action

The current module inherit `crm.claim` while the `state` attribute doesn't exist anymore. I made some changes to use the `stage_id` instead but I'm not so sure it's a good idea. I'm open to suggestions.
From what I understand, if I add this inside the class that inherit this class, it should append in place the methods that are missing. I'll have to test that out, I can probably strip it from there without problem.