WebIDL brand checks incorrectly throw when using getters/methods on makeSafed WebIDL classes

[easrng]

Version: Deno 2.1.9

I was making a SafeURL class with makeSafe from primordials when I ran into this error:

const SafeURL = makeSafe(URL, class SafeURL extends URL {});

let safeUrl=new SafeURL("https://example.com")
console.log(safeUrl.href)
// throws TypeError: Illegal invocation
//    at Module.assertBranded (ext:deno_webidl/00_webidl.js:1142:11)
//    at URL.get href (ext:deno_url/00_url.js:594:12)

Here's a version that doesn't rely on the primordials:

class SafeURL extends URL {}
Object.defineProperties(SafeURL.prototype, Object.getOwnPropertyDescriptors(URL.prototype))
Object.setPrototypeOf(SafeURL.prototype, null)
Object.freeze(SafeURL.prototype)
Object.freeze(SafeURL)

let safeUrl=new SafeURL("https://example.com")
console.log(safeUrl.href)

No other runtime I tested throws with this code, and throwing seems incorrect (though I haven't read the WebIDL spec lol)
Would also be nice if the brand checks stopped using symbols, though I don't think that'll be an issue for me here