When istiod reconciles Gateway API resources, it does not respect the `istio.io/rev` label on the resources. This means you cannot perform a revisioned upgrade of the gateway by changing the `istio.io/rev` label because the 2.6 controlplane will always try to reconcile the gateway regardless of the label.

In contrast, an upstream istiod will not reconcile gateway resources that do not match the istiod's rev so when you change the rev label on the gateway resource, the old istiod will stop reconciling that resource.

To reproduce:

1. Create a ClusterWide SMCP
2. Deploy bookinfo + bookinfo gateway api
3. Change the rev label on the gateway resource
4. Make some change to observe that the gateway resource is still be reconciled e.g. delete the underlying gateway deployment and see that it gets recreated by istiod.