Fix openapi schema (#2013)

* fix openapi spec

fix openapi schema bug

* fix api schema bug

pkg/simple/client/k8s/null_client.go

@@ -0,0 +1,45 @@
+package k8s
+
+import (
+	application "github.com/kubernetes-sigs/application/pkg/client/clientset/versioned"
+	istio "istio.io/client-go/pkg/clientset/versioned"
+	"k8s.io/client-go/discovery"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+	kubesphere "kubesphere.io/kubesphere/pkg/client/clientset/versioned"
+)
+
+type nullClient struct {
+}
+
+func NewNullClient() Client {
+	return &nullClient{}
+}
+
+func (n nullClient) Kubernetes() kubernetes.Interface {
+	return nil
+}
+
+func (n nullClient) KubeSphere() kubesphere.Interface {
+	return nil
+}
+
+func (n nullClient) Istio() istio.Interface {
+	return nil
+}
+
+func (n nullClient) Application() application.Interface {
+	return nil
+}
+
+func (n nullClient) Discovery() discovery.DiscoveryInterface {
+	return nil
+}
+
+func (n nullClient) Master() string {
+	return ""
+}
+
+func (n nullClient) Config() *rest.Config {
+	return nil
+}