Similarly to its local counterpart, Special:GlobalGroupRights should be aware of restricted groups.
Acceptance criteria
- If a group is restricted and user cannot be added to it, the checkbox is disabled and an annotation is shown
- If a group is restricted and uses private conditions, an annotation is shown and conditions are evaluated on saving
- If performer evaluates a private condition on saving, a relevant hook is called, similarly to Special:UserRights
- If saving groups fails, an error is displayed, outlining why the groups weren't saved