Allow attributedTo in a status to be an embedded object (#6238)

app/services/activitypub/fetch_remote_status_service.rb

@@ -30,7 +30,7 @@ class ActivityPub::FetchRemoteStatusService < BaseService
   end
 
   def actor_id
-    first_of_value(@json['attributedTo'])
+    value_or_id(first_of_value(@json['attributedTo']))
   end
 
   def trustworthy_attribution?(uri, attributed_to)