Add overload for unary `!` operator to call std::ops::Not

[TomAFrench]

After https://github.com/noir-lang/noir/pull/4999 we'll have a negation trait, we should allow calling this through an operator overload similar to how we do for arithmetic operations.

[TomAFrench]

@asterite This could also be a good issue to take a look at once you have bandwidth. We've got operator overloads implemented for infix operators but not unary operators.

We'd only need to implement this in the elaborator so changes to this file would be sufficient afaik (you can also see the infix implementation in there).

[TomAFrench]

I mention the elaborator as the legacy type-checking pass also implements trait dispatch and without re-implementing it there you may encounter some test case failures on here and we don't need to worry about fixing those.