We currently allow the user to dismiss the login menu via Ctrl+C. This
leaves them in a bad state where they're not auth'ed but have an input
prompt. In the extension, this isn't a problem because we don't allow
the user to dismiss the login screen.
Testing: I confirmed that Ctrl+C no longer dismisses the login menu.
This is an alternative (simpler) fix for a [community
PR](https://github.com/openai/codex/pull/3234).