Run RPi builds during CE nightly pipelines

What does this MR do?

Run RPi builds during CE nightly pipelines

- Add RPi builds back to nightly pipelines now that they
  have much faster build times.

Closes https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/6774

Signed-off-by: Balasankar "Balu" C <balasankar@gitlab.com>

Now that RPi builds are relatively faster, we can bring them back to nightly pipelines.

Related issues

Closes #6774 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened