docs(getting-started): update stackablectl op install output

[NickLarsenNZ]

### Run getting_started.sh via
- [x] `stackablectl`
- [x] `helm`

[NickLarsenNZ]

In the helm case, I see a warning (but the script still succeeds):

warning: couldn't attach to pod/my-pod, falling back to streaming logs: unable to upgrade connection: container my-pod not found in pod my-pod_default

I tried adding --wait but the option is being removed and apparently unused by kubectl run. We might needs to add a sleep or something.

This worked each time when I manually ran it (~4 times):

kubectl run my-pod \
  --stdin --tty --quiet --restart=Never \
  --image docker.stackable.tech/stackable/zookeeper:3.9.2-stackable0.0.0-dev -- \
  bin/zkCli.sh -server simple-zk-server-default:2282 ls / > /dev/null && \
  kubectl logs my-pod && \
  kubectl delete pods my-pod

In terms of correctness in the docs, this is fine.

[maltesander]

LGTM!