Revert "Merge branch 'backport-fix-remaining-prepend-lines' into 'master'"

What does this MR do?

The change in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31379 caused QA jobs to fail with LoadError: cannot load such file -- /home/lib/gitlab

This is because when the QA images are built, they're built from the qa subfolder, so the code in parent directories isn't available.

Access to that code will require a change to the way images are built. But for now I'd like to revert the change so the QA jobs can run.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65607

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team