Accept any x25519 public key

[nickray]

Fixes https://github.com/ycrypto/salty/issues/31.

[nickray]

A bit stumped why https://github.com/ycrypto/salty/actions/runs/5457535558/jobs/9931719708 is failing even after adding the schemas.

[sosthene-nitrokey]

using

    #[test_wycheproof(
        "wycheproof/wycheproof-tests/tests/eddsa_test.json",
        "eddsa_verify_schema.json"
    )]

Fixes the error for me.

[nickray]

using

    #[test_wycheproof(
        "wycheproof/wycheproof-tests/tests/eddsa_test.json",
        "eddsa_verify_schema.json"
    )]

Fixes the error for me.

Everything works locally, just not in CI, hence the stump.