[FIX] mrp: fix bad workorder-move link

Workorder _action_confirm works in batch and is designed to
link workorders and moves per production.

Original code breaks the 'per production' constraint by linking
moves from all productions to workorders of the last one when
called on workorders from multiple productions.

closes odoo/odoo#86633

Task: 2797201
Signed-off-by: Arnold Moyaux <arm@odoo.com>

addons/mrp/models/mrp_workorder.py

@@ -451,7 +451,7 @@ class MrpWorkorder(models.Model):
             bom = self.env['mrp.bom']
             moves = production.move_raw_ids | production.move_finished_ids
 
-            for workorder in self:
+            for workorder in workorders:
                 bom = workorder.operation_id.bom_id or workorder.production_id.bom_id
                 previous_workorder = workorders_by_bom[bom][-1:]
                 previous_workorder.next_work_order_id = workorder.id