Merge branch '403325-fix-error-budget' into 'master'

Revert to using SearchService for user autocomplete

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/122289



Merged-by: Eulyeon Ko <5961404-euko@users.noreply.gitlab.com>
Approved-by: Mayra Cabrera <mcabrera@gitlab.com>
Approved-by: Eulyeon Ko <5961404-euko@users.noreply.gitlab.com>
Approved-by: Ravi Kumar <rkumar@gitlab.com>
Reviewed-by: Mayra Cabrera <mcabrera@gitlab.com>
Reviewed-by: Eulyeon Ko <5961404-euko@users.noreply.gitlab.com>
Co-authored-by: maddievn <mvanniekerk@gitlab.com>