Draft: Support backward compatibility for check-packages-functionality

What does this MR do and why?

Describe in detail what your merge request does and why.

Content

• Support backward compatibility for check-packages-functionality

check-packages-functionality is implemented in 17.3. Before that, there was no such job. Thus, instead of checking the job, we need to check the statuses of all jobs the previous stage, which is staging_upload.

This commit adds another code path for this situation, with rspec tests.

Ref: gitlab-com/gl-infra/delivery#20290 (closed)

NOTE: The need for this MR, or the version where the backward compatibility is needed, will change depend on the backports from Distribution team of omnibus-gitlab!7802 (merged) and omnibus-gitlab!7830 (merged).

Author Check-list

• Has documentation been updated?