wpseo_robots does not working correctly

Hello everyone, I’m just faced issue when trying to remove noindex from search page on my wordpress site.

I’m using this code snippet from other topics:

add_filter('wpseo_robots', 'yoast_no_home_noindex', 999);

function yoast_no_home_noindex($string) {
    $string = "";
    if (is_home() || is_front_page() || is_search()) {
        $string= "index,follow";
    }
    return $string;
}

But when I’m reload my search page, in the inspector I see this meta tag:

<meta name="robots" content="noindex, follow, index,follow">

I’m using wordpress 5.7.5 and yoast 17.6