add_action('init', 'register_yoast_meta_rest_api');
function register_yoast_meta_rest_api() {
    register_meta('post', '_yoast_wpseo_title', array(
        'show_in_rest' => true,
        'single' => true,
        'type' => 'string',
    ));
    register_meta('post', '_yoast_wpseo_metadesc', array(
        'show_in_rest' => true,
        'single' => true,
        'type' => 'string',
    ));
}