Running the tests clears the user's login token

1. Run the system test services
2. Login - `uv run blueapi login`
3. Check login works - `uv run blueapi controller devices`
4. Run tests - `uv run pytest tests/unit
5. See that you've been logged out - `uv run blueapi controller devices` - gives auth error

This is a pain even if it's not really a bug in blueapi itself.