[site-reviews] Unprotect the assigned rating meta keys

/**
 * Unprotect Site Reviews' hidden meta keys used for assigned rating counts
 *
 * Use this if you have cloned a page that had assigned reviews, this will
 * allow you to remove the obsolete meta keys with the Custom Fields MetaBox.
 *
 * This snippet should not be kept active!
 *
 * @param bool $protected
 * @param string $metaKey
 * @return bool
 */
add_filter('is_protected_meta', function ($protected, $metaKey) {
    if (in_array($metaKey, ['_glsr_average', '_glsr_ranking', '_glsr_reviews'])) {
        return false;
    }
    return $protected;
}, 10, 2);