Make attachment cleanup jobs a noop if the setting is disabled.

lib/pleroma/workers/attachments_cleanup_worker.ex

@@ -17,12 +17,14 @@ def perform(%Job{
           "object" => %{"data" => %{"attachment" => [_ | _] = attachments, "actor" => actor}}
         }
       }) do
+    if Pleroma.Config.get([:instance, :cleanup_attachments], false) do
       attachments
       |> Enum.flat_map(fn item -> Enum.map(item["url"], & &1["href"]) end)
       |> fetch_objects
       |> prepare_objects(actor, Enum.map(attachments, & &1["name"]))
       |> filter_objects
       |> do_clean
+    end
 
     {:ok, :success}
   end