Alerts service was completely removed:
- https://gitlab.com/gitlab-org/gitlab/-/merge_requests/50913
- https://gitlab.com/gitlab-org/gitlab/-/merge_requests/53534

Alerts service metric was deprecated
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/59899 and we can
safely remove it https://gitlab.com/gitlab-data/analytics/-/issues/8609.