fix: allow updating when JWKS URI is set (#3935)

[phooijenga]

The validator rejects updates when JSONWebKeysURI is non-empty and JSONWebKeys is not nil, but this field is set to new(x.JoseJSONWebKeySet) in Client's BeforeSave.

Related issue(s)

#3935

Checklist

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Further Comments

[aeneasr]

Awesome, thank you! 🎉 Your contribution makes Ory better :)