Consider not running `letsencrypt-test` for pipelines triggered from gitlab-org/gitlab
The letsencrypt-test
job can only be broken by a change in omnibus-gitlab, so it would make sense to disable the job for pipelines triggered from gitlab-org/gitlab, e.g. https://gitlab.com/gitlab-org/build/omnibus-gitlab-mirror/-/pipelines/628460885.
That way the triggered pipeline could hopefully finish a bit earlier.