"local" - searches for passkeys on the local system, or sync'd through a
password manager.
email - queries BI's directory for passkeys belonging to the user. Note:
The private key component of the passkey resides with the FIDO2
authenticator on which it was created. Only the key identifier is
stored in Beyond Identity's directory.
"autofill" - same as "local" but may be associated with a UI component. TODO:
describe this option's usage.
Method of locating FIDO2 passkeys.