[Docs]: Appsmith backup and restore for k8s improvements

### Problem Statement

There are a couple of issues on this page: https://docs.appsmith.com/getting-started/setup/instance-management/appsmithctl
# k8s namespaces
All `kubectl` console commands shall include namespace. Now, in some cases there is one, while in others there's no.
examples:

# Restore from backup
```
4. Open the docker.env file and update the below parameters:
```
None of the standard text editors is available on provided image: `vim, nano, gedit, xed`... therefore it's not clear how user supposed to edit and save this file. Makes sense to mention text editor which is included in the image (if any) or add some hints about installing it.

### Use Cases / User query reference

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### Audio/Video Recording

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### Product Requirements Document

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### Other Relevant Links

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### Checklist

- [X] Reviewed existing documentation to ensure this request is not duplicated.
- [X] Attached relevant media or supporting materials like links to the PRD, feature recordings, Slack or Discord links, and any other relevant resources.