ErrorEvent.error is `null` when handling an uncaught error from a worker

[cowboyd]

Version: Deno 2.1.6

When handling an uncaught error from the main thread, the error field on the resulting error event is null. The expected behavior is that it would be, if not the exact error, an error with the same message and perhaps a cause indicating that it was thrown in the worker.

[cowboyd]

I've created a minimal reproduction of this issue.

https://github.com/cowboyd/deno-issue-27753

Also, this seems related to #12221