[site-reviews] Only require email field if rating is 1-star or less

/**
 * Require the email field if the submitted rating is 1-star or less
 *
 * Make sure to set the email field as not required in the Settings
 * otherwise this will do nothing.
 *
 * Requires: Site Reviews v5.16
 *
 * @param array $rules
 * @param \GeminiLabs\SiteReviews\Request $request
 * @return array
 */
add_filter('site-reviews/validation/rules/normalized', function ($rules, $request) {
    if ($request->rating < 2) {
        $rules['email'] = 'required|email';
    }
    return $rules;
}, 10, 2);