This story aims to remove x-k8s.io group from Gateway API CRD VAP deployed by Cluster Ingress Operator.

The proposal is that given OSSM already disables any reconciliation on this group, and that these APIs are already prefixed with X (eg.: XListenerSet), they don't pose as a risk for CIO or Gateway API, and would allow customers willing to test a 3rd party solution with new features (eg.: ListenerSet) to do so.

This implementation should cover:

• Remove "gateway.networking.x-k8s.io'" from https://github.com/openshift/cluster-ingress-operator/blob/d9509d0c52ee07a853b750dfe39b1447b163f94c/manifests/01-validating-admission-policy.yaml#L21
• Validate on a new cluster that x-k8s.io can be installed
• Validate on an upgraded cluster that x-k8s.io can be installed (QE team)
• Adjust tests to validate that x-k8s.io can be added, and validate that OSSM disregard this kind of resource