Run gitlab-depscan in both dev and .com
Currently we are only running dependency scanning in the dev omnibus-gitlab pipeline example. To improve visibility, we should also run this in the .com omnibus-gitlab pipeline.
In the past, this was avoided because building packages to do a scan is costly, but as discovered in https://dev.gitlab.org/gitlab/omnibus-gitlab/-/merge_requests/184, we don't need to build packages to create the omnibus manifest file that gitlab-depscan uses as input.
Followup from #129 (closed).