[Doc] Update a few things in Step 3 of getting started with Pulsar using Kubernetes Docs

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### What issue do you find in Pulsar docs?

When following the docs for Running Pulsar in K8s there are a couple of steps that could be more clear. Both steps are in Step 3: Use Pulsar client to produce and consume messages

### What is your suggestion?

1. First suggestion is when it mentions to get the service URLs to connect to your Pulsar client. It would be useful to maybe mention to hold on to those URLs and that they will be needed later for configuring the Pulsar client
2. 2nd suggestion is for 5. in Step 3. It makes no mention to go back to the toolset container. Even though this lack of clarity can be glossed over by the fact that most folks will probably figure it out, it is still fair to remember that for a beginner trying to just follow the steps for the first time ease and clarity of steps will make all the difference.

### Any reference?

https://pulsar.apache.org/docs/3.0.x/getting-started-helm/

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

Open the referenced getting-started-helm documentation and review Step 3, “Use Pulsar client to produce and consume messages.” Update the instructions to say to retain the service URLs and to return to the toolset container for step 5; the section should be unambiguous for a beginner following it sequentially.

Written by the indexing model from the issue text.