[✨] Allow preventing Form action

[wmertens]

Is your feature request related to a problem?

When JS is enabled and you're using a Form only to redirect, it would save a server roundtrip to redirect immediately.

Describe the solution you'd like

action only fires after a custom onSubmit$ and only if the event is not prevented.

This is what the docs AI expects as the API

Describe alternatives you've considered

special attributes

Additional context

preventdefault is already used to allow action to run locally, so it will mean passing a fake event to onSubmit$ and checking if the default was prevented.

[gioboa]

We moved this issue to qwik-evolution repo to create a RFC discussion for this.
Here is our Qwik RFC process thanks.