Fix email helper test

extract module to override upstream test

upstream MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/88800

jh/spec/config/skip_specs.yml

@@ -123,7 +123,3 @@
   description:
     - "User registration when accepting an invite doesn't ask me what I would like to do"
     - 'User registration when accepting an invite sends me to the group activity page'
-- file_path: 'spec/helpers/emails_helper_spec.rb'
-  description:
-    - "EmailsHelper#header_logo there is a brand item without a logo returns the default header logo"
-    - 'EmailsHelper#header_logo there is no brand item returns the default header logo'