Improve UI for empty states - Propless SDC

This will need actual design later, but +1 for the current MVP proposal by @jessebaker!

This needs only a trivial addition to \Drupal\experience_builder\Form\ComponentPropsForm::buildForm().

Thanks for taking this on, @shyam_bhatt! 🥳

Just nits, but left suggestions. I think any /ui owner can make final tweaks and merge this :)

Merging, thanks for moving on this so quickly.

Automatically closed - issue fixed for 2 weeks with no activity.