Look, everything can be eaten, but why would you want to? The magic would disappear!
Also, although the Canavalia Ensiformis is sometimes used for fodder for animals (in Brazil it’s called the ‘Pig Bean’), it is slightly toxic to humans.
In short: no. Leave it on the windowsill, don’t put it in your dinner.
If, by chance, your youngster picked it up and popped it in, they wouldn’t be poisoned. The beans would have to be consumed in large quantities to be truly noxious.