Merge branch 'smriti-486532/audit_event_for_user_name_change' into 'master'

Added audit event for user name change

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/167484



Merged-by: Aakriti Gupta <agupta@gitlab.com>
Approved-by: Sam Figueroa <sfigueroa@gitlab.com>
Approved-by: Aakriti Gupta <agupta@gitlab.com>
Reviewed-by: Aakriti Gupta <agupta@gitlab.com>
Co-authored-by: smriti <sgarg@gitlab.com>