gemini-cli installations done through brew having Keychain perpetually unavailable

### What happened?

Initially I installed gemini-cli via homebrew, but any time an extension had a sensitive variable it would fail to store it in the keychain, defaulting to file storage.

When I switched to npm installed gemini-cli, everything works as designed.

### What did you expect to happen?

Either we have feature parity on using keychain on homebrew VS npm installed versions, or a disclaimer is added that keychain will not be used to store sensitive variables.

### Client information

Client Information

Run `gemini` to enter the interactive CLI, then run the `/about` command.

```console
> /about
CLI Version 0.39.0 │
│ Git Commit 398f78dca │
```

### Login information

Auth Method : vertex-ai

### Anything else we need to know?

_No response_