Extend Filter kl_checkout_item to support $cart_item

Please extend the kl_checkout_item Filter to allow passing $cart_item along to further allow developers to customise the payload before it is sent to Klaviyo (e.g. interim Product Bundle support). In wck-cart-rebuild.php

From: add_filter(‘kl_checkout_item’,’kl_modify_checkout_item’,1,2);
To: add_filter(‘kl_checkout_item’,’kl_modify_checkout_item’,1,3);

From: $event_data[‘$extra’][‘Items’][] = apply_filters( ‘kl_checkout_item’, $item, $product );
To: $event_data[‘$extra’][‘Items’][] = apply_filters( ‘kl_checkout_item’, $item, $product, $values );