fix: allow PI cancel if linked asset is cancelled

(cherry picked from commit b961321de5)

erpnext/controllers/buying_controller.py

@@ -716,6 +716,8 @@ class BuyingController(SubcontractingController):
 						asset.purchase_date = self.posting_date
 						asset.supplier = self.supplier
 					elif self.docstatus == 2:
+						if asset.docstatus == 2:
+							break
 						if asset.docstatus == 0:
 							asset.set(field, None)
 							asset.supplier = None