login method
Implementation
Future<void> login({Map<String, String> extraParameters = const {}}) async {
final codeVerifier = _createCodeVerifier();
await _saveCodeVerifier(codeVerifier);
final grant = _getAuthGrant(codeVerifier);
final authUri = _buildAuthorizationUri(
grant,
extraParameters: extraParameters,
);
await _launchUrl(authUri);
}