MSI and Posting a Shipment via API

### Preconditions (*)
- Version 2.3.2
- Manage Stock = Yes
- Product Inventory level is 0 for a product that is on an order in the Processing status

### Steps to reproduce (*)
- Post a Shipment via the API (`order/{id}/ship`) to the order mentioned in the pre-requisites

### Expected result (*)

- the shipment gets created in Magento

### Actual result (*)

- API responds with: `"message": "Could not save a shipment, see error log for details"`
- if you try to create a shipment via the UI, you get the below error

Reproduce the failure against version 2.3.2 using the documented order/{id}/ship API endpoint, with Manage Stock enabled and zero inventory for a product on a Processing order. Compare the API and UI error paths and inspect the error log; done means the shipment is created successfully through the API under these conditions.

Written by the indexing model from the issue text.