Cannot release shipment in case disable Vnext

Description

Preconditions:

• Disable Vnext.
• A variant, A, with In stock = 5, Back order = 5.

Steps to reproduce:

1. Go to Commerce Manager.
2. Create Order1 with variant A, quantity 5 --> Order1 is ordered with In stock quantity.
3. Create Order2 with variant A, quantity 5 --> Order2 is ordered with Backorder quantity.
4. Add a payment for Order1.

Expected:
The Release button is enabled. Admin can release the shipment for Order1.

Actual:
Release buttion is disabled. Admin cannot release the shipment for Order1.