ci: Fix `gitpod-docker-image` job and enable verify jobs in MR pipelines

What does this merge request do and why?

⚠ This MR needs !3127 (merged) merged first.

This MR includes make gitlab-update, make gitlab-shell-update, and make gitlab-workhorse-update commands to update these default services since these commands were removed from the gdk reconfigure command in this MR: !3007 (diffs). It turns out that these commands are necessary to set up Gitpod.

Here's an example of a successful pipeline: https://gitlab.com/gitlab-org/gitlab-development-kit/-/pipelines/862239993.

Closes #1813 (closed)

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.