when we create a return product, selected partner_id on picking is wrong.

Hello,

Steps to reproduce :

- Create a sale order with customer "X" as partner_id, confirm the sale order, create the invoice and validate the invoice.
- Create a claim with the customer "X" as partner_id
- In "Product Return" tab, select the invoice, lines are populated below.
- Press "New Products Return", it opens a pop-up
- Press "Create picking", an error warns you to choose line with a same address.
- On line details, choose warranty address, for example "ASUSTeK" (e.g. as explained, where the customer has to send back the products) : the product is sent back to ASUSTeK to manage the repair or replacement.
--> A picking is created with :
     - a move with destinatation address ASUSTeK : it's right.
     - the partner_id on the picking is ASUSTeK instead of customer "X", it's X who sent back the product. (as a supplier who sent a product)

Regards,

Romain