GitLab Shell's sshd configuration does not observe `service.internalPort`
## Origin
The following discussion from !1249 should be addressed:
- [ ] @balasankarc started a [discussion](https://gitlab.com/gitlab-org/charts/gitlab/-/merge_requests/1249#note_323062848): (+1 comment)
> @twk3 @WarheadsSE So, I think this MR is ready for another review. I've added a "Development decisions" section in the MR description along with a sample additional settings file which got me to spin up a GitLab Shell pod without errors. Few things to note
>
> 1. `service.externalPort` is not "required" because it will take the value of the `internalPort`. Also, we don't expect users to normally change this. I am not opposed to making this also a `required` setting from a practical perspective, but it is technically not needed.
> 1. I have skipped validation for `global` values entirely since that should come from the root values.yaml file. We can add a validation for that as a next iteration.
## Details
The sshd always runs on `2222` (from configmap!) despite `containerPort: {{ .Values.service.internalPort }}` in the Deployment template. :bug:
issue