PT-4735 - Fix saved invoice amount for net orders
PT-4735 - Fix saved invoice amount for net orders

If we have a net order, we need to set the tax rate for each order
detail to zero. Otherwise, the total invoice amount of an order will
eventually be recalculated in Order#calculateInvoiceAmount to include
the taxes.

shopwareLabs/SwagBackendOrder,shopwareLabs/SwagBackendOrder,shopwareLabs/SwagBackendOrder