Ubuntu keychain support is broken

### Describe the bug

There are two bugs:

1. the documentation https://docs.github.com/en/copilot/how-tos/copilot-cli/set-up-copilot-cli/troubleshoot-copilot-cli-auth#keychain-access-failure is wrong. Under Ubuntu (see below for version), If `secret-tool` is not installed, running `sudo apt install libsecret-1-0 gnome-keyring seahorse` doesn't install it. You also need to run `sudo apt install libsecret-tools` (please fix the docs)
2. Once `secret-tool` is correctly installed, as confirmed by `command -v secret-tool`, Copilot-CLI still fails to find `secret-tool` and use it. I tried to log out of my SSH connection to Ubuntu, log in again and try again: didn't help

### Affected version

GitHub Copilot CLI 1.0.9

### Steps to reproduce the behavior

1. Make sure `secret-tool` is installed, by running `command -v secret-tool`:
2. start Copilot CLI by running `copilot`
3. login with `/login` (in my case, this requires quite a few clicks since I use the SSO login of my organization)
4. Copilot CLI complains that `The system vault (keychain, keyring, password manager, etc.) is not available. You may need to install one.` So it actually doesn't see `secret-tool`. Please fix

### Expected behavior

When `secret-tool` is installed and I run `copilot`, then `/login`, Copilot CLI should be able to see `secret-tool` and safely store my token in the keychain, instead of prompting me to accept the risk and store the token in the plain text config file instead

### Additional context

Linux version:
```
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 24.04.1 LTS
Release: 24.04
Codename: noble
```
I'm connecting to Ubuntu from Windows via SSH with the Windows Terminal. The remote Ubuntu server is a headless server, but I would expect a key manager to work (once installed) regardless of that

Start with the linked Copilot CLI troubleshooting documentation and the `copilot` `/login` flow on Ubuntu 24.04 over SSH. Reproduce the behavior with `command -v secret-tool` after installing the listed packages, then trace why the CLI does not detect it. Done means the documentation includes `libsecret-tools` and login can use the installed keychain without falling back to plain-text token storage.

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