fix: add actionable errors for GCE long running operations

[parthea]

Fixes b/280938007

Googlers see go/surface-actionable-errors-lro-gce

When an error occurs during an extended operation when using the python compute client, currently users only receive the error code and the error message, which is not helpful.

google.api_core.exceptions.BadRequest: 400 BAD REQUEST

The proposed solution is to provide users with actionable error information, surfacing the errors field which contains actionable errors.

google.api_core.exceptions.BadRequest: 400 BAD REQUEST
INCOMPATIBLE_BACKEND_SERVICES: Validation failed for instance group 'projects/<REDACTED>/zones/us-central1-a/instanceGroups/my-instance-group-1': backend services 'projects/<REDACTED>/global/backendServices/my-backend-service-1' and 'projects/<REDACTED>global/backendServices/my-backend-service-2' point to the same instance group but the backends have incompatible balancing_mode. Values should be the same.

[parthea]

I'll add tests if go/surface-actionable-errors-lro-gce is approved.