Merge branch '2ndary-email-delete' into 'master'

Clarify secondary email deletion

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/142050



Merged-by: Evan Read <eread@gitlab.com>
Approved-by: Bogdan Denkovych <bdenkovych@gitlab.com>
Approved-by: Adil Farrukh <afarrukh@gitlab.com>
Co-authored-by: Jonathan Glassman <jglassman@gitlab.com>