Make the 'package-and-qa' job wait for downstream 'Trigger:qa-test' job

What does this MR do?

In the omnibus-gitlab-mirror pipelines, the Trigger:measure-memory job can take some time (up to 40 minutes) to run, and that can lead the upstream gitlab-org/gitlab job to timeout.

Since gitlab-org/gitlab's schedule:package-and-qa job is only interested in the result of the omnibus-gitlab-mirror's Trigger:qa-test job, this MR makes gitlab-org/gitlab's schedule:package-and-qa polls for omnibus-gitlab-mirror's Trigger:qa-test instead of the whole pipeline, so that the QA status would be reported as soon as Trigger:qa-test passes/fails.

This should mitigate #33272 (closed).

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] 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

• Example of a failed Trigger:qa-test: https://gitlab.com/gitlab-org/gitlab/-/jobs/314866341
• Example of a successful Trigger:qa-test: TBD