TOTP MFA support

[dotjon0]

To support TOTP MFA as documented at https://cloud.google.com/identity-platform/docs/admin/enabling-totp-mfa

[cbenhagen]

This should be fixed in firebase_auth - v4.9.0:
FEAT(auth): TOTP (time-based one-time password) support for multi-factor authentication (#11420). (3cc1243c)

[dotjon0]

Any updates to this please? Can see https://pub.dev/packages/firebase_auth/changelog#490 but there are no docs? Does this support Windows, macOS, iOS and Android?