Called by:

• Mobilizon.Federation.ActivityPub.Transmogrifier.do_handle_incoming_accept_join_event (L858)
• Mobilizon.Federation.ActivityPub.Transmogrifier.do_handle_incoming_reject_join (L905)
• Mobilizon.GraphQL.API.Participations.accept (L63)
• Mobilizon.GraphQL.API.Participations.reject (L83)