Allow Group Owners to change (primary) emails to non-verified domains for Enterprise Users
Background
With Enterprise Users, it is not possible for a person to change their primary email address once they have been claimed as an Enterprise User.
Sometimes, especially when offboarding from a company, a person may want to keep their GitLab account but their company should be able to remove them from groups/projects and still let them retain their account.
Proposal
Group owner has the ability to change primary email address for Enterprise User. Once this is changed, they are no longer an Enterprise User.
Workaround
Top level group owner can contact GitLab Support to modify the primary email address of their enterprise users. #412966 (comment 1755809657)