[RFC] Call onSubmit when there are errors

[Sawtaytoes]

Right now, there's no way to know what's wrong when your form won't submit if you didn't properly design your form.

The intention is you build validation in your form to display the right error messages, but if something's not working, you need feedback in onSubmit that the button was clicked and the form state.

That would assist with debugging when you have a bug in your code related to validations and aren't getting any feedback on which errors are causing the form to not submit.