Describe the bug

"Share available quantities to sell" option is enabled, "All shops" is selected, in the BO > Orders > Order page > when we try to update the product quantity => an alert "Error! There are not enough products in stock." but the Available quantity > 0

Steps to Reproduce

Steps to reproduce the behavior:

1. Enable Multishop Context.
2. Go to BO > Advanced Parameters > Multistore page
3. Create a new Group GroupA
   
4. Create a new shop ShopA related to the GroupA
   
5. Create a productA in all shops
6. Quantity of the productA in the shopA = 12
7. ShopA => create an order from the FO with the last product created (quantity ordered = 1)
8. Go to BO > Advanced Parameters > Multistore page
9. Edit the Group by default Default
10. Enable "Share available quantities to sell"
    
11. Go Back to the Order => last order created => All shops selected
12. Try to increase the quantity => you have an alert

"Error!
There are not enough products in stock."

But the Available quantity > 0

If you select the shopA => ok

PS: 1768: https://drive.google.com/file/d/1Q7ScfJ51BsYZWb8cMJA8pIuPeiN5H4si/view?usp=sharing => ok

Additional information

• PrestaShop version: 177x
• PHP version: 7.2