fix: use of incorrect attribute

(cherry picked from commit fb32d2c)

erpnext/accounts/doctype/payment_entry/payment_entry.py

@@ -1563,7 +1563,7 @@ def get_outstanding_reference_documents(args):
 				d["bill_no"] = frappe.db.get_value(d.voucher_type, d.voucher_no, "bill_no")
 
 		# Get negative outstanding sales /purchase invoices
-		if args.get("party_type") != "Employee" and not args.get("voucher_no"):
+		if args.get("party_type") != "Employee":
 			negative_outstanding_invoices = get_negative_outstanding_invoices(
 				args.get("party_type"),
 				args.get("party"),