Clean up CheckboxWithLabel refactor

[luacmartins]

Problem

I noticed a few things that should have been different with the CheckboxWithLabel refactor:

1. onChange was renamed to onInputChange in Form.js. We should update this and rename it in all usages of CheckboxWithLabel.
2. The usage in Form.stories.js is incorrect. We should NOT pass onPress or isChecked to CheckboxWithLabel since Form provides the "onChange" handler automatically. We also use it as an uncontrolled input in Form and passing isChecked means that we would have to control the component state in Form. We should instead move this logic to CheckboxWithLabel, so that the interface looks as that of an uncontrolled input.
3. Calling React.forwardRef inline means that some props passed automatically from Form might not be defined when React runs its prop validation. We should call it in export default spreading all the props passed to the component, similar to what we do in AddressSearch

Why is this important?

We need to have the correct interface to work with Form.js

Solution

Described in each point above.