nativeSignIn method
Runs the whole UAE Pass sign-in hand-off natively — presenting the login UI, switching to the native UAE Pass app when installed, and resuming via the platform's own deep-link mechanism — and returns the resulting authorization code.
authorizeUrl (pre-built by Dart from UaePassConfig/state) is
only used by iOS's native WKWebView flow; Android's vendored AAR
builds its own authorize request from the config already pushed by
setUpEnvironment and ignores it.
Throws a PlatformException with code "ERROR" on failure or
cancellation; callers are expected to classify the message the same
way UaePassKit classifies an error query parameter.
Implementation
Future<String?> nativeSignIn({
required String state,
required Uri authorizeUrl,
}) {
throw UnimplementedError('nativeSignIn() has not been implemented.');
}