Restore quickstarts / smoke tests on GHA

[coryan]

We would like to run at least one REST-based and one gRPC-based smoke test on the macOS and Windows builds. We used to do this with the quickstarts, but we can use a custom integration test or a quickstart for this.

We have an example of how to do this on Linux:

https://github.com/googleapis/google-cloud-cpp/blob/b0d1730e68d5696f20278564c210d2652adadcfe/.github/workflows/external-account-integration.yml#L63-L73

Something like this should work for the other builds.