Bug 262613

As per https://github.com/WICG/webcrypto-secure-curves/pull/24 the "alg" JWK member is now ignored during JWK import, and missing during JWK export for Ed25519 keys.

Safari correctly handles the latter but not the former, the "alg" JWK member is not ignored during import.

```
const jwk = {
  crv: "Ed25519",
  x: "2OGJY9gJ1IfZVJrMrsZ0Ln7rok2KDTsUt-PK6gaJPcw",
  kty: "OKP",
  alg: "this should now be ignored",
};

crypto.subtle.importKey("jwk", jwk, "Ed25519", true, ["verify"]).then((key) => {
  crypto.subtle.exportKey("jwk", key).then((exportedJwk) => {
    if (exportedJwk.alg) {
      console.log("❌ alg should be missing");
    }
  });
});
```