Potential runtime error in kube_cache.GetK8sGateways

[hhovsepy]

Happens on Kiali master.
Start the Kiali when K8s GW CRDs are not created.
Apply K8s GW CRDs.
Immediately refresh the Kiali page.
Runtime panic nil pointer error in logs, on any of those methods kube_cache.GetK8sGateways.

This is because the userClient.IsGatewayAPI() return 'true' when the CRDs exist, but in fact the k8sgatewayLister was not created while starting the Kiali first time.
https://github.com/kiali/kiali/blob/master/kubernetes/cache/kube_cache.go#L397

And any call to k8sgatewayLister causes nil error.
https://github.com/kiali/kiali/blob/master/kubernetes/cache/kube_cache.go#L1504

[jshaughn]

@hhovsepy , I think this issue should have been closed by #7008, no? I'll close, please re-open if I am wrong.