Explicitly handle the GET and HEAD errors

lib/pleroma/workers/rich_media_worker.ex

@@ -22,6 +22,10 @@ def perform(%Job{args: %{"op" => "backfill", "url" => _url} = args}) do
       when type in [:invalid_metadata, :body_too_large, :content_type, :validate] ->
         {:cancel, type}
 
+      {:error, type}
+      when type in [:get, :head] ->
+        {:error, type}
+
       error ->
         {:error, error}
     end