DEV: Trigger an event when a user is granted admin or moderation. (#17663)

app/models/concerns/roleable.rb

@@ -35,6 +35,7 @@ module Roleable
     auto_approve_user
     enqueue_staff_welcome_message(:moderator)
     set_default_notification_levels(:moderators)
+    DiscourseEvent.trigger(:staff_granted, self, :moderator)
   end
 
   def revoke_moderation!
@@ -47,6 +48,7 @@ module Roleable
     auto_approve_user
     enqueue_staff_welcome_message(:admin)
     set_default_notification_levels(:admins)
+    DiscourseEvent.trigger(:staff_granted, self, :admin)
   end
 
   def revoke_admin!