login abstract method
Validates a GitHub authorization code and either logs in the associated user or creates a new user account if the GitHub account ID is not yet known.
This method exchanges the authorization code for an access token using
PKCE, then authenticates the user.
If a new user is created an associated UserProfile is also created.
Implementation
_i2.Future<_i3.AuthSuccess> login({
required String code,
required String codeVerifier,
required String redirectUri,
});