[FIX] website_sale: copied line is linked with the original order

- Create a sale.order with a product with an optional product
- Confirm order A
- Copy this order A, a new order B is created
--> Issue: the new line of order B are linked with an line of order A

closes odoo/odoo#83536

Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>

addons/website_sale/models/sale_order.py

@@ -365,7 +365,7 @@ class SaleOrderLine(models.Model):
 
     name_short = fields.Char(compute="_compute_name_short")
 
-    linked_line_id = fields.Many2one('sale.order.line', string='Linked Order Line', domain="[('order_id', '!=', order_id)]", ondelete='cascade')
+    linked_line_id = fields.Many2one('sale.order.line', string='Linked Order Line', domain="[('order_id', '=', order_id)]", ondelete='cascade', copy=False)
     option_line_ids = fields.One2many('sale.order.line', 'linked_line_id', string='Options Linked')
 
     def get_sale_order_line_multiline_description_sale(self, product):