Make PublicKeyCredentialCreationOptions Serializable

[pahlevani]

Closes gh-16431

It doesn’t appear to be fixed yet—there hasn’t been an accepted or merged change addressing it in any released version. It’s possible there was a misunderstanding involving the class names PublicKeyCredentialRequestOptions and PublicKeyCredentialCreationOptions, or a mix-up with issues gh-16431 and gh-16432.

Related issues:

• WebAuthn + Redis doesn't work; Redis defaults to JdkSerializationRedisSerializer, WebAuthn classes lack Serializable interface, WebAuthn mixins missing for GenericJackson2JsonRedisSerializer #16328 is the parent issue of Make PublicKeyCredentialCreationOptions Serializable #16431.
• This pull request resolves WebAuthn: credential registration fails with an unknown credential type error #17164 and includes a test covering the fix.