[Bug] LineItem is instantiated without a factory

[lruozzi9]

SyliusRefundPlugin version affected: 1.4.0

Description
In

RefundPlugin/src/Converter/LineItem/OrderItemUnitLineItemsConverter.php

Line 70 in 66c42d3

return new LineItem(

the LineItem entity is created statically without a factory class

Steps to reproduce
Add an extension of the LineItem class. When you class entityManager->flush(); it will fail because it is expected to be an instance of LineItem extension.

Possible Solution
Use a factory class.