Resolve "Broken master due to goldiloader"

What does this MR do?

This removes a forgotten auto_include in app/services/ci/register_job_service.rb. Related to https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5409

Are there points in the code the reviewer needs to double check?

I don't think so.

Why was this MR needed?

Because ~"broken master"!

Does this MR meet the acceptance criteria?

• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #5725 (closed)