"On hand" value influences sorting of "on demand" products/variants

[filipefurtad0]

Description

Follow-up from #13533.
When sorting in descending order, on demand variants appear first, however, it becomes noticeable that - despite being hidden from users, in this case - on hand value influences the ordering, of on demand products/variants.

Expected Behavior

When two products are both on On demand, they should be ordered alphabetically, and not as a function of the respective (hidden) on hand values.

Actual Behaviour

When two products are both on On demand, they are ordered according to the respective (hidden) on hand values.

Steps to Reproduce

1. As a hub, visit the product page
2. Set up two products named A and B, with one variant each
3. Set up stock for these variants as A on_hand = 5 and B on_hand = 10
4. On each variant, tick the On demand option; the on_hand value should disappear.
5. Order the products by On hand stock levels, to be ascending in order -> notice that variant A should appear at the top
6. Edit variant B, setting the on hand to a value lower that to 5, let's say 2; make sure it is still set as on_demand.
7. Now visit/refresh the /products page and re-order the products in descending order -> product variant B now appears at the top

Animated Gif/Screenshot

Workaround

Use other filters together with the On hand columnt find the required variants.

Severity

bug-s3: a feature is broken but there is a workaround

Your Environment

• Version used: should be in prod since version 5.2.5
• Browser name and version: Firefox 143.0.1
• Operating System and version (desktop or mobile): Ubuntu 22.04

Possible Fix