CI: Extend test coverage to include downstream customers

[akoumpa]

Is your feature request related to a problem? Please describe.
As part of our weekly deep-testing and release pipeline, we want to ensure that we don't break any customer's code.

Describe the solution you'd like
Trigger customer's tests as part of our weekly and release test pipelines. If compute permits, cadence could be shorter (e.g., daily).

Describe alternatives you've considered
N/A

Additional context
N/A