Upload produced packages in the SBRP PRs

[ViktorHofer]

Looks like SBRP produced packages don't get uploaded as a pipeline artifact in PRs. It would be great to do that so that a PR doesn't need to get built locally to see the produced packages.

[MichaelSimons]

Isn't this the standard arcade behavior irrespective of source build?

[ViktorHofer]

Nope. There is an opt-in when you use the eng/common YML templates but that uploads the entire artifacts directory I think.

[MichaelSimons]

[Triage] Looking into this, it is a problem with the source build arcade infra for repo legs. This is going to be changing with the UB work once we enable flat flows. Once this is done, the repo source build legs will be going away. It is uncertain what the SBRP build will look like after this.