feat(next): add allowForbiddenValues validation option

[lukad]

This adds an option that allow passing values to false schemas. This would normally result in a validation error but in v0 we explicitly clear values provided to a false schema:

json-schema-form/src/helpers.js

Lines 451 to 461 in 4efb07e

	function clearValuesIfNotVisible(fields, formValues) {
	fields.forEach(({ isVisible = true, name, inputType, fields: nestedFields }) => {
	if (!isVisible) {
	// TODO I (Sandrina) think this doesn't work. I didn't find any test covering this scenario. Revisit later.
	formValues[name] = null;
	}
	if (inputType === supportedTypes.FIELDSET && nestedFields && formValues[name]) {
	clearValuesIfNotVisible(nestedFields, formValues[name]);
	}
	});
	}

This option will achieve the same goal, but in a more straight forward way. It will also be disabled by default.