swatch-system-conduit should report "gcp" as cloud_provider rather than "google"

When console.redhat.com implemented GCP detection originally, we tagged all GCP instances with cloud_provider: "google".

During investigation of https://issues.redhat.com/browse/ESSNTL-3114, one of the engineers realized that the inventory UI expected "gcp" rather than "google", and they made the appropriate change for the insights reporter specifically.

swatch-system-conduit should use the same value.

Verification:

• given a host registered to the customer portal from GCP, when the org is synced via conduit, it should be represented in HBI w/ cloud_provider=gcp