Reject announce payload if object is nil (#33570)

app/lib/activitypub/activity/announce.rb

@@ -3,6 +3,7 @@
 class ActivityPub::Activity::Announce < ActivityPub::Activity
   def perform
     return reject_payload! if delete_arrived_first?(@json['id']) || !related_to_local_activity?
+    return reject_payload! if @object.nil?
 
     with_redis_lock("announce:#{value_or_id(@object)}") do
       original_status = status_from_object