At the moment, user could set annotations on `gateway.spec.infrastructure.annotations` to provision internal LB.

This is short-term solution and we need e2e test to cover it.

[From Miciah] It is kind of like the "TestInternalLoadBalancer" test in cluster-ingress-operator, except the test needs to specify the annotation in `Gateway.spec.infrastructure.annotation` in addition to checking for it on the service: https://github.com/openshift/cluster-ingress-operator/blob/1ea51fcc3ce39c6f8a2e2c74921fc1584478b0f5/test/e2e/operator_test.go#L1179-L1267`