fix: missing subresources for v1alpha3.BackendTLSPolicy (#4245)

Co-authored-by: zirain <zirain2009@gmail.com>

Author: k8s-infra-cherrypick-robot

apis/v1alpha3/backendtlspolicy_types.go

@@ -24,6 +24,7 @@ import (
 
 // +genclient
 // +kubebuilder:object:root=true
+// +kubebuilder:subresource:status
 // +kubebuilder:deprecatedversion:warning="The v1alpha3 version of BackendTLSPolicy has been deprecated and will be removed in a future release of the API. Please upgrade to v1."
 type BackendTLSPolicy v1.BackendTLSPolicy