fielservice_sale fix link with invoices

Author: hparfr

fieldservice_sale/models/sale_order_line.py

@@ -145,5 +145,6 @@ def _field_service_generation(self):
 
     def _prepare_invoice_line(self):
         res = super()._prepare_invoice_line()
-        res.update({"fsm_order_id": self.fsm_order_id.id})
+        # by default: don't group fsm_orders on account.move.line
+        res.update({"fsm_order_ids": [(6, 0, [self.fsm_order_id.id])]})
         return res