How to add product's category list on order preview modal window in WooCommerce

functions.php

<?php
/**
* Adds product's category list on admin order preview modal window in WooCommerce
* @since 3.3.0
* @see https://pamula.sk/woocommerce-ako-zobrazit-kategorie-produktu-v-nahlade-objednavky/
* 
* Please REMOVE the opening <?php tag before placing into functions.php
* Prosim ODSTRANTE otvaraciu <?php znacku pred umiestnenim do functions.php
*/

add_filter( 'woocommerce_admin_order_preview_line_item_columns', 'rp_add_product_category_column', 10, 2 );

function rp_add_product_category_column( $_columns ) {

	$newcol = [ 'category' => __( 'Category', 'woocommerce' ) ];
	$items  = count( $_columns );

	return array_merge( array_slice( $_columns, 0, 1 ), $newcol, array_slice( $_columns, 1, $items - 1 ) );

}

add_filter( 'woocommerce_admin_order_preview_line_item_column_category', 'rp_add_product_category_list', 10, 2 );

function rp_add_product_category_list( $result, $_item ) {

	$result = wc_get_product_category_list( $_item['product_id'], ', ', '', '' );

	return $result;
}