[Admin] Update a submit status when conference is passed

![image](https://user-images.githubusercontent.com/944409/176850168-31f8de91-e0cb-49af-8bdc-30be256133bd.png)

I did shit and made that status as "rejected" by mistake (see https://github.com/jolicode/starfleet/issues/280) and now I can't switch it back to accepted (impossible in user UI, and validation is blocking me in admin).