Require gcp authentication method be clear based on input
Address issue where no means of authentication (or two conflicting options) are provided in non-interactive mode
Cover invalid scenarios where authentication method is set in non-ccs mode
ocm create cluster --ccs --provider=gcp --dry-run=true jjjj
Error: either wif-config or GCP service account file must be specified
ocm create cluster --ccs --provider=gcp --dry-run=true jjjj --wif-config=test --service-account-file=key.json
Error: can't use both wif-config and GCP service account file at the same time
Issue: https://issues.redhat.com/browse/OCM-11699