fix: Use the item's cost centre instead of the Invoice's

Co-authored-by: Deepesh Garg <42651287+deepeshgarg007@users.noreply.github.com>
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index aa2fe29..65dbe17 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -836,7 +836,7 @@
 							"against": supplier_or_customer,
 							dr_or_cr: flt(item.discount_amount),
 							dr_or_cr + "_in_account_currency": flt(item.discount_amount),
-							"cost_center": self.cost_center,
+							"cost_center": item.cost_center,
 							"project": self.project
 						}, account_currency, item=self)
 					)