E2E: staging only VSA test

What does this MR do and why?

Due to VSA dashboards requiring a fairly complicated set of preconditions which are not possible to fabricate from within the test using just the api, this implements E2E spec that uses a pre-existing project on staging.gitlab.com to have at least some kind of safety net on E2E level that validates correctness of generated lifecycle metrics.

Closes #416679 (closed)

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