Fix DeliveryWorker not to call failure_tracker when inbox_url is unavailable (#13482)

app/workers/activitypub/delivery_worker.rb

@@ -23,12 +23,14 @@ class ActivityPub::DeliveryWorker
 
     perform_request
   ensure
+    if @inbox_url.present?
       if @performed
         failure_tracker.track_success!
       else
         failure_tracker.track_failure!
       end
     end
+  end
 
   private