PASSWORD is unset by code-server

### Is there an existing issue for this?

- [X] I have searched the existing issues

### OS/Web Information

- Web Browser: Chrome
- Local OS: Windows 10
- Remote OS: Ubuntu 20.04
- Remote Architecture: amd64
- `code-server --version`: v4.10.0

```
code-server: v4.10.0
Code: 1.75.1
Commit: 441438abd1ac652551dbe4d408dfcec8a499b8bf
Date: 2023-02-13T16:47:00.619Z
Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/[125.0.0.0](http://125.0.0.0/) Safari/537.36
```

### Steps to Reproduce

1. Set an environmental variable `PASSWORD` in the docker environment
2. Launch code server and open terminal
3. `echo $PASSWORD` <- does not exist

### Expected

My `PASSWORD` env var should still exist in the launched code-server terminal, like all of my other env vars set in an identical manner.

### Actual

I have the `PASSWORD` environmental variable set for an unrelated tool. When I launch code-server, I no longer have that environmental variable set. Would it be possible to not unset it?

I launch code-server like this:
```
code-server /mnt/code --user-data-dir /mnt/code/.vscode --auth none --bind-addr 0.0.0.0:8888 --extensions-dir ${HOME}/.local/share/code-server/extensions --disable-telemetry
```

And this is in a dockerized kubernetes container (lingo might be off...).

### Logs

_No response_

### Screenshot/Video

_No response_

### Does this bug reproduce in native VS Code?

No, this works as expected in native VS Code

### Does this bug reproduce in GitHub Codespaces?

I did not test GitHub Codespaces

### Are you accessing code-server over a secure context?

- [X] I am using a secure context.

### Notes

I saw this issue: https://github.com/coder/code-server/issues/6698 which isn't really the same but vaguely related.