lib: replace MessageEvent with undici's

undici's MessageEvent is better tested and has a complete WebIDL implementation for validation. Not only this, but it's also used in Node's current WebSocket implementation. There are a large number of webidl-related issues in the current MessageEvent, such as not implementing MessageEvent.prototype.initMessageEvent, not validating arguments passed to its constructor (https://github.com/nodejs/node/pull/51771), not validating the values passed to the constructor (such as not validating that ports is a sequence, not converting origin to a USVString, etc.), and other issues.