[K8s] Fail to launch service on GKE cluster

[Michaelvll]

To reproduce:
sky serve up -n test examples/serve/http_server/task.yaml --cloud kubernetes --cpus 2

I 06-05 05:36:42 cloud_vm_ray_backend.py:4164] Auto-stop is not supported for Kubernetes clusters. Skipping.
I 06-05 05:36:51 cloud_vm_ray_backend.py:3315] Job submitted with Job ID: 24

W 06-05 05:37:00 backend_utils.py:2806] Port 30001 not exposed yet. If the cluster was recently started, please retry after a while. Additionally, make sure your LoadBalancer is configured correctly. 
W 06-05 05:37:00 backend_utils.py:2806] To debug, run: kubectl describe service
AssertionError: Did not get endpoint for controller.

[Michaelvll]

Oops, this issue seems unrelated to the fix #3634, but caused by the sky-serve-controller not having the ports opened during the first launch. Closing this for now.