[FIX] purchase: Wrong Fiscal position in multicompany

Steps to reproduce:

 -Create company A
 -Create company B
 -Admin user with both companies but currently in company B
 -Create Demo user only with company B
 -Create fiscal position A to company A
 -Create fiscal position B to company B
 -Create vendor with fiscal position A with company A and the same vendor with fiscal position B in company B
 -Create product and add the vendor created before
 -Set like Create a draft purchase order
 -Logging with Demo user
 -Create sale order with one sale order line with route make to order
 -Validate sale order

Bug:

 The purchase order created by sale order had the fiscal position company A.

Closes #23561
opw:1825098

addons/purchase/models/purchase.py

@@ -1012,7 +1012,7 @@ class ProcurementRule(models.Model):
     def _prepare_purchase_order(self, product_id, product_qty, product_uom, origin, values, partner):
         schedule_date = self._get_purchase_schedule_date(values)
         purchase_date = self._get_purchase_order_date(product_id, product_qty, product_uom, values, partner, schedule_date)
-        fpos = self.env['account.fiscal.position'].with_context(company_id=values['company_id'].id).get_fiscal_position(partner.id)
+        fpos = self.env['account.fiscal.position'].with_context(force_company=values['company_id'].id).get_fiscal_position(partner.id)
 
         gpo = self.group_propagation_option
         group = (gpo == 'fixed' and self.group_id.id) or \