[FR] Expose MFA info in UserRecord

[zhxnlai]

Is your feature request related to a problem? Please describe.
UserRecord.java does not parse a user's multi factor enrollment information, which is documented here.

{
  uid: 'some-uid',
  // ...
  multiFactor: {
    enrolledFactors: [
      // 2FA with SMS as 2nd factor.
      {
        uid: '53HG4HG45HG8G04GJ40J4G3J',
        phoneNumber: '+16505551234',
        displayName: 'Work phone',
        enrollmentTime: 'Fri, 22 Sep 2017 01:49:58 GMT',
        factorId: 'phone',
      },
    ],
  },
};

Describe the solution you'd like
Add a mfaInfo field to UserRecord. Example from the Node.js SDK: https://github.com/firebase/firebase-admin-node/blob/master/src/auth/user-record.ts#L78

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

We also need this

[rafhofman]

Bumping up

[JaredEzz]

I also need this functionality. https://cloud.google.com/identity-platform/docs/admin/manage-mfa-users All methods from this documentation should be supported