[Split Checkout] Cart page not displaying "Update" button

[filipefurtad0]

Description

If the stock is reduced below the order requirements, then the user is redirected to the /cart page, where the amount should be corrected and the "Update" button clicked.

On split checkout the update button is not displaying, if the stock restriction occurs on:

• the /payment step (when proceeding to /summary) -> see PR Checks stock restrictions on checkout split (system spec) #8939
• the /summary step (when concluding the order)

Expected Behavior

After stock restriction, the user gets redirected to the /cart page and the "Update" button is displayed.

Actual Behaviour

After stock restriction, the user gets redirected to the /cart page but the "Update" button is not displayed.

Steps to Reproduce

1. As a customer, while on the /payment or /summary page
2. ...Reduce the stock as admin...
3. and, as a customer, click on "Next - Order Summary"

Animated Gif/Screenshot

On the /details step:

On the /payment or/summary steps: