Update gclb recipe for new requirements.

[naemono]

While testing #8779 I found some new requirements for loadbalancing in GKE clusters, notably:

1: A domain name is required when using cert-manager to generate the certificates to be used for the GCP loadbalancer, as GCP tooling now attempts to parse the certificate and fails without it.
2: The /* path no longer works for the Exact type of ingress.

[prodsecmachine]

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