Invalid JS or JS that throws an error shows a timeout error

[twschiller]

Describe the bug

• https://pixiebrix.slack.com/archives/C0436P48QHY/p1720814810505619

To Reproduce

Steps to reproduce the behavior:

function(args) {
  throw new Error("foo");
}

Actual behavior

Throws a messenger error after 3 retries

Expected behavior

Throws the JS error (either invalid function, or the error thrown by the JS at runtime)