During onOrderItemUpdate() calls $order_item->getQuantity() and $order_item->original->getQuantity() have different types of data

Problem/Motivation

During some development, I have noticed the issue that we have different shipping methods for invoice and order which is created from this invoice, after some debugging I have noticed that on \Drupal\commerce_shipping\EventSubscriber\OrderItemSubscriber::onOrderItemUpdate()
$order_item->getQuantity() returns '1' as a string, but $order_item->original->getQuantity() returns '1.00' as a float, so basically these two are not equal and it force shipping refresh, after that shipping method is changing.

Proposed resolution

Us the Field item equals method instead.