Javascript error on submit for an invalid form

[jcgueriaud1]

Describe the bug

When I submit a form that is invalid I have a javascript error.

Uncaught (in promise) ValidationError: There are validation errors in the form.
 - fullName - NotNull: must not be null
    at BinderRoot.submitTo (chunk-UA3PFYSQ.js?v=5a255b3a:1929:13)

Expected-behavior

I don't expect a javascript error for a validation error that is handled in my form.
Especially because the documentation says:

Submission failures are handled automatically, so there is no need to do an explicit try-catch.

https://vaadin.com/docs/latest/hilla/guides/forms/binder-load#saving-data

Reproduction

Run this project:
https://github.com/jcgueriaud1/hilla-example-form

Go to the home page and click on save, see the error in the console.

System Info

Vaadin 24.4.4

[cromoteca]

The current behavior handles validation errors, but the main error itself is not handled and goes to the browser, which puts it in the console.
Either we add some default handling, or we change the documentation to better explain what happens.
An example of full handling is in the AutoForm.
Let's update the documentation and maybe add a simple example of error handling.