Show the commit-sha for pre-release versions

What does this MR do?

This adds the SHA for pre-release (nightlies), as otherwise it would be hard to determine which version is running exactly. These versions are currently not deployed to GitLab.com.

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52050

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides