This was breaking
`hack/install-ate.sh --delete-all` with
`--delete-demo-autoscaled-workerpool is not supported on GKE`
Also removed the custom usage message for
--deploy-demo-autoscaled-workerpool. This was duplicate with the default
message:
Before:
```
Demo: demo-autoscaled-workerpool
--deploy-demo-autoscaled-workerpool Deploy demo-autoscaled-workerpool
--delete-demo-autoscaled-workerpool Delete demo-autoscaled-workerpool
--deploy-demo-autoscaled-workerpool Deploy autoscaled-workerpool demo (HPA + prometheus-adapter + counter workload)
```
After:
```
Demo: demo-autoscaled-workerpool
--deploy-demo-autoscaled-workerpool Deploy demo-autoscaled-workerpool
--delete-demo-autoscaled-workerpool Delete demo-autoscaled-workerpool
```
- [x] Tests pass
- [x] Appropriate changes to documentation are included in the PR