Faker for `Rule.regex(..., { invert: true })`

For the regex validations, we found a library to mock those, but we need a library to _not_ mock those. We could just mock arbitrary strings and check against the regex until we don't match. Seems risky with infinite loops. Maybe there's a way with `randexp`. We could alter the regex to be `(?!(<the-provided-regex>))` but I'm seeing a lot about why that's not good.