chore(passport): Passkeys userHandle generation redo

[betimshahini]

Description

• Changes passkey identity to be based on a custom userId generated on the server-side, as opposed to the existing method of taking the authenticator credentialId and using that for identifying the account on our system.
• Adds userId to the challenge, so it can be verified on the server-side during registration.
• Adds credentialId to the verification process of the passkey authentication, so the credentialId that was provided by authenticator at registration is the same as the one that's providing the assertion now.

Related Issues

• Closes chore(passport): Passkeys username encoding & validation #2695

Testing

• Old passkey registrations no longer work
• Registration of new passkey results in a userId of the format wa_(42 character random hex string) in Passport Settings.
• Same account & identity is resolved when logging on with the newly-generated passkey subsequently

Checklist

• I have read the CONTRIBUTING guidelines
• I have tested my code (manually and/or automated if applicable)
• I have updated the documentation (if necessary)