Add wrappers with default values for MFA methods

[Widcket]

Changes

In Authentication.swift, all the methods that have optional parameters have wrappers in an extension to provide default values. There a were a couple of methods that did not have said wrapper:

• login(withOOBCode:mfaToken:bindingCode:), in which bindingCode is optional.
• multifactorChallenge(mfaToken:types:authenticatorId:), in which types and authenticatorId are optional.

This PR adds wrappers for those methods.

Testing

• This change adds unit test coverage
• This change has been tested on the latest version of the platform/language or why not

Checklist

• I have read the Auth0 general contribution guidelines
• All existing and new tests complete without errors
• All active GitHub checks have passed