Error parsing does not support mfa_token field when the error is a 403 mfa_required error

[rmberg]

Checklist

• I have looked into the README and have not found a suitable solution or answer.
• I have looked into the documentation and have not found a suitable solution or answer.
• I have searched the issues and have not found a suitable solution or answer.
• I have upgraded to the latest version of this SDK and the issue still persists.
• I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• I agree to the terms within the Auth0 Code of Conduct.

Description

I am attempting to implement a backend call to OAuth.LoginWithPassword and when the error returned is an MFA required error, I don't have the ability to access the mfa_token returned in the error response. This is needed so that I can trigger the MFA challenge flow properly.

Expectation

The Error struct should support an MFAToken field

Reproduction

1. Given a call to LoginWithPassword for a user that has MFA enabled
2. an error is returned with status code 403 and error code mfa_required
3. there is not a way to retrieve the mfa_token from the error response

Auth0 Go SDK version

v1.4.0