There are some missing environment variables in `copilot help environment`

### Describe the bug

When I run `copilot help environment`, the content displayed is incomplete. I can see the full version [here](https://docs.github.com/en/copilot/reference/copilot-cli-reference/cli-command-reference#environment-variables), and I hope it can be added to the `copilot help environment` command output.

### Affected version

GitHub Copilot CLI 1.0.40.

### Steps to reproduce the behavior

1. `copilot help environment`

### Expected behavior

I expected that all environment variables, including experimental settings, would be displayed in the `copilot help environment` output.

### Additional context

_No response_

首先找到 `copilot help environment` 命令的实现，并将其输出与链接的 CLI 参考进行比较。更新该命令的环境变量列表，以包含缺失的设置和实验性设置，然后运行 `copilot help environment`，验证显示的列表是否与参考一致。

由索引模型根据 Issue 内容生成。