Allow error handling for situations where iframe fails to load

[aldenquimby]

My team occasionally runs into this error with Retool Embed:

Error: Nonce provided is invalid or already redeemed

Is there any way for us to catch the error and act accordingly? Our fix is to re-generate the embed URL and re-render the iframe, and then things work, but it looks like we'd need Retool to post a message to the parent frame to know there is an error

For example it would be great to be able to use onData:

<Retool url={url} onData={((msg) => {
  if (msg === "Error: Nonce provided is invalid or already redeemed") {
    // re-generate URL
  }
})}
/>