[Request] Push code using `TwoFactorUserIdScheme` to this remote

[phrohdoh]

The blog post mentions:

And then retrieve this in our LoginCallback using:

var result = await HttpContext.AuthenticateAsync(IdentityConstants.TwoFactorUserIdScheme);
var userId = result.Principal.FindFirstValue("sub");

But that code (and the related code) are not in this repo.

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My call to AuthenticateAsync is failing (response property Succeeded = false) and I am not sure why so I am hoping to see I have missed something simple.