Retry 401 errors on replies fetching (#28788)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/services/activitypub/fetch_replies_service.rb

@@ -36,7 +36,21 @@ class ActivityPub::FetchRepliesService < BaseService
     return collection_or_uri if collection_or_uri.is_a?(Hash)
     return unless @allow_synchronous_requests
     return if invalid_origin?(collection_or_uri)
-    fetch_resource_without_id_validation(collection_or_uri, nil, true)
+
+    # NOTE: For backward compatibility reasons, Mastodon signs outgoing
+    # queries incorrectly by default.
+    #
+    # While this is relevant for all URLs with query strings, this is
+    # the only code path where this happens in practice.
+    #
+    # Therefore, retry with correct signatures if this fails.
+    begin
+      fetch_resource_without_id_validation(collection_or_uri, nil, true)
+    rescue Mastodon::UnexpectedResponseError => e
+      raise unless e.response && e.response.code == 401 && Addressable::URI.parse(collection_or_uri).query.present?
+
+      fetch_resource_without_id_validation(collection_or_uri, nil, true, request_options: { with_query_string: true })
+    end
   end
 
   def filtered_replies