docs: update example notebooks spec (#7107)

It looks like the notebook images no longer rely on start.sh.

It looks like the Docker images now use the init system to run jupyterlab with the correct arguments
https://github.com/kubeflow/kubeflow/blob/master/components/example-notebook-servers/jupyter/Dockerfile

I could find no start.sh script in the repo

components/notebook-controller/README.md

@@ -22,18 +22,6 @@ spec:
       containers:
         - name: my-notebook
           image: kubeflownotebookswg/jupyter:master
-          args:
-            [
-              "start.sh",
-              "lab",
-              "--LabApp.token=''",
-              "--LabApp.allow_remote_access='True'",
-              "--LabApp.allow_root='True'",
-              "--LabApp.ip='*'",
-              "--LabApp.base_url=/test/my-notebook/",
-              "--port=8888",
-              "--no-browser",
-            ]
 ```
 
 The required fields are `containers[0].image` and (`containers[0].command` and/or `containers[0].args`).