Observe secondary email addresses when adding a member

This change was first introduced in merge request
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/62024.

Changelog: changed

changelogs/unreleased/329319-observe-secondary-email-addresses-when-adding-a-member.yml

----
-title: Observe secondary email addresses when adding a member
-merge_request: 62024
-author:
-type: changed