requestOtp method
Request the user receive a One Time Password either via SMS or Email
Implementation
Future<String> requestOtp(emailOrPhone) async {
String url = '$authEndpoint/user/otp';
Map body = {"emailOrPhone": emailOrPhone};
Response res = await dio.post(url, data: body);
_storeOtpRequestNonce(res.data);
return res.data["nonce"];
}