examples for client_metadata.jwks all include 'use' in the key but it's not required by spec

[jogu]

The spec says:

Using what it supports and its preferences, the Wallet selects the public key to encrypt the Authorization Response based on information about each key, such as the kty (Key Type), use (Public Key Use), alg (Algorithm), and other JWK parameters. The alg parameter MUST be present in the JWKs.

But every example we have includes 'use'. It's good to have some examples that show it, but probably we should have one or two that don't too.

(searching for "kty" is a good way to find the examples)