After 7 days of repeated delivery failures, give up on inbox (#5131)

- A successful delivery cancels it out
- An incoming delivery from account of the inbox cancels it out

app/controllers/activitypub/inboxes_controller.rb

@@ -32,6 +32,7 @@ class ActivityPub::InboxesController < Api::BaseController
     end
 
     Pubsubhubbub::UnsubscribeWorker.perform_async(signed_request_account.id) if signed_request_account.subscribed?
+    DeliveryFailureTracker.track_inverse_success!(signed_request_account)
   end
 
   def process_payload