Fix #10975. Avoid Prometheus export error by using default label core as K8s group if not set (#10976)
Fix #10975. Avoid Prometheus export error by using default label core as K8s group if not set (#10976)


istio/istio,smawson/istio,geeknoid/istio,geeknoid/istio,geeknoid/istio,istio/istio,smawson/istio,geeknoid/istio,geeknoid/istio,smawson/istio,smawson/istio,geeknoid/istio,smawson/istio,istio/istio,istio/istio,smawson/istio,istio/istio