[GCP IMDS] Use fully qualified name

[Arkelenia]

Use the fully-qualified name for the GCP IMDS endpoint

Description

This PR replaces the current IMDS endpoint http://metadata/computeMetadata/v1/... with the fully-qualified name version http://metadata.google.internal/computeMetadata/v1/....

The current state assumes the presence of google.internal as a search domain to work properly which may not be the case when the endpoint is resolved from a container or a Kubernetes pod running on a GCP node.

Status

ready for review

Checklist (tick everything that applies)

• [ ] Code linting (required, can be done after the PR checks)
• [ ] Documentation
• [ ] Tests
• [ ] ICLA (required for bigger changes)