[site-reviews] Modify validation rules based on rating

/**
 * @param \GeminiLabs\SiteReviews\Request $request
 */
add_filter('site-reviews/validate/custom', function (array $rules, $request): array {
    $rating = $request->rating ?? 0;
    if ($rating < 4) {
        return $rules;
    }
    $rules['title'] = 'required';
    $rules['content'] = 'required';
    $rules['name'] = 'required';
    $rules['email'] = 'required|email';
    $rules['terms'] = 'accepted';
    return $rules;
}, 10, 2);