handleMobileAuthWithOtp
Starts mobile authentication using OTP as described in Mobile authentication with OTP.
Caveats:
- A user needs to be authenticated
 - Only one OTP Mobile Authentication flow can occur at a given moment
 
Future<void> handleMobileAuthWithOtp(String data)
await Onegini.instance.userClient
    .handleMobileAuthWithOtp(data)
    .catchError((error) {
        print("OTP Mobile authentication request failed: " + error.message);
    });