Fix invalid mixer CRD (#19917)
Fix invalid mixer CRD (#19917)

Fixes postsubmit test failures like
https://prow.istio.io/view/gcs/istio-prow/logs/integ-k8s-115_istio_postsubmit/231
smawson/istio,istio/istio,smawson/istio,smawson/istio,istio/istio,istio/istio,smawson/istio,istio/istio,smawson/istio,istio/istio,smawson/istio