Fix label selector in Using Source IP tutorial

Before:
```sh
controlplane $ kubectl delete svc -l run=source-ip-app
No resources found
```
```sh
k get svc --show-labels
NAME           TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE     LABELS
clusterip      ClusterIP      10.110.247.112   <none>        80/TCP         28m     app=source-ip-app
kubernetes     ClusterIP      10.96.0.1        <none>        443/TCP        49m     component=apiserver,provider=kubernetes
loadbalancer   LoadBalancer   10.111.123.206   <pending>     80:31111/TCP   9m59s   app=source-ip-app
nodeport       NodePort       10.108.129.31    <none>        80:32503/TCP   22m     app=source-ip-app
```
After:
```sh
controlplane $ kubectl delete svc -l app=source-ip-app
service "clusterip" deleted
service "loadbalancer" deleted
service "nodeport" deleted
```

Update source-ip.md

Update source-ip.md

Update source-ip.md

content/en/docs/tutorials/services/source-ip.md

@@ -425,7 +425,7 @@ the `service.spec.healthCheckNodePort` field on the Service.
 Delete the Services:
 
 ```shell
-kubectl delete svc -l run=source-ip-app
+kubectl delete svc -l app=source-ip-app
 ```
 
 Delete the Deployment, ReplicaSet and Pod:

content/ja/docs/tutorials/services/source-ip.md

@@ -399,7 +399,7 @@ client_address=198.51.100.79
 Serviceを削除します。
 
 ```shell
-kubectl delete svc -l run=source-ip-app
+kubectl delete svc -l app=source-ip-app
 ```
 
 Deployment、ReplicaSet、Podを削除します。

content/ko/docs/tutorials/services/source-ip.md

@@ -426,7 +426,7 @@ HTTP 헬스 체크를 생성하여
 서비스를 삭제한다.
 
 ```shell
-kubectl delete svc -l run=source-ip-app
+kubectl delete svc -l app=source-ip-app
 ```
 
 디플로이먼트, 레플리카셋 그리고 파드를 삭제한다.

content/zh/docs/tutorials/services/source-ip.md

@@ -387,7 +387,7 @@ __跨平台支持__
 删除服务：
 
 ```console
-$ kubectl delete svc -l run=source-ip-app
+$ kubectl delete svc -l app=source-ip-app
 ```