[site-reviews] Prevent author of assigned page from submitting a review

/**
 * Prevent authors from submitting reviews for their own post
 * @param bool $isValid
 * @param \GeminiLabs\SiteReviews\Request $request
 * @return bool|string
 */
add_filter('site-reviews/validate/custom', function ($isValid, $request) {
    $postIds = explode(',', $request->assigned_posts);
    foreach ($postIds as $postId) {
        $post = get_post($postId);
        if ($post && intval($post->post_author) === get_current_user_id()) {
            return __('You cannot review your own product.');
        }
    }
    return $isValid;
}, 10, 2);