Clean up generated code for basic `type: "object"`

[mwildehahn]

Right now it does something like:

	public static function check(mixed $input, string $pointer): blocks_suggestions_callback_validator_properties_unfurl_t {
		$typed = Constraints\ObjectConstraint::check($input, $pointer, self::$coerce);

		$output = dict[];

        return $typed;
    }

we shouldn't assign output