fix: Use default Cost Center of the Company for additional discount (#…

…37234)

fix: Set cost center as default company cost center 

When Discount Accounting in enabled in Selling Settings, use Company default Cost Center while making GL entries for additional_discount_account

erpnext/controllers/accounts_controller.py

@@ -1491,7 +1491,7 @@ def make_discount_gl_entries(self, gl_entries):
 						"account": self.additional_discount_account,
 						"against": supplier_or_customer,
 						dr_or_cr: self.base_discount_amount,
-						"cost_center": self.cost_center,
+						"cost_center": self.cost_center or erpnext.get_default_cost_center(self.company),
 					},
 					item=self,
 				)