Clouddriver - consider using `cloudProvider` metric

[karlskewes]

Per upstream PR available in 1.25.x: https://github.com/spinnaker/clouddriver/pull/5252/files

This might:

• simplify metric queries with regex matching label serviceEndpoint=~".*$AwsRegion.*" in both clouddriver.jsonnet and spinnaker-aws-platform.jsonnet, other?
• be suitable in a key metrics section of clouddriver.jsonnet showing per cloudProvider RED or just errors.

Examples:

• before:

  orchestrations_seconds_count{cloudProvider="kubernetes", container="clouddriver", <snip>}

• after:

  orchestrations_seconds_count{container="clouddriver", <snip>}