SDK: Errors from oauth responses are not deserialized properly in .NET SDK

[p89]

v. 1.51.0

Hi Team, during integration of this library I've found out a contract mismatch between the Error & Errors classes and the sample error responses from endpoints like oauth2/token.

Example error message from fusionAuth service:

{
    "error": "invalid_grant",
    "error_description": "The user credentials are invalid.",
    "error_reason": "invalid_user_credentials"
}

Error.cs

public class Error {

    public string code;

    public IDictionary<string, object> data;

    public string message;

    public Error with(Action<Error> action) {
      action(this);
      return this;
    }
  }

The DefaultRestClient always return null values as errors:

if (clientResponse.statusCode >= 300)
            clientResponse.errorResponse = JsonConvert.DeserializeObject<Errors>(result.Content.ReadAsStringAsync().Result, DefaultRESTClient.SerializerSettings);

Steps to reproduce:

Use the following method with incorrect credentials and try to read the errors:

Task<ClientResponse<AccessToken>> ExchangeUserCredentialsForAccessTokenAsync(
      string username,
      string password,
      string client_id,
      string client_secret,
      string scope,
      string user_code);