Fix auth check

[vcheung-stripe]

This fixes an issue where the extension always prompts for login when you have a project name set.

To check if you're authenticated, we run stripe config --list and parse the TOML output. The problem is when you set a project name, stripe config --list doesn't return valid TOML, so we don't know that you're authenticated.

This fixes it by explicitly setting stripe config --list --project-name default which prints out the config file verbatim so that it's always valid TOML.