Ed25519 JWK import should ignore the "alg" JWK member

[Filip Skokan]

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");
    }
  });
});
```

[Filip Skokan]

WPT update for the draft spec change https://github.com/web-platform-tests/wpt/pull/42333

[Radar WebKit Bug Importer]

<rdar://problem/116806236>

[Javier Fernandez]

I'm working on a patch for this bug.

[Javier Fernandez]

Pull request: https://github.com/WebKit/WebKit/pull/21006

[Javier Fernandez]

It seems Chrome reviewers have doubts regarding the decision to remove the 'alg' field from the JWK import operation's logic. 

I'd rather wait until there is more consensus before merging the patch.

[Javier Fernandez]

It seems that FF implementation ignores the "alg" JWK member, as it passes the related tests [1]. It'd be useful to know WebKit's position on this regard, given than apparently Chrome's concerns are debatable, from what I could extract from the conversation in the mentioned Chrome bug. 

[1] https://wpt.fyi/results/WebCryptoAPI/import_export/okp_importKey_Ed25519.https.any.html?label=experimental&label=master&aligned