fix: payment entry voucher_type error (#35779)

* fix: payment entry `voucher_type` error (#35779)

* fix: payment entry `voucher_type` error

* chore: linters

(cherry picked from commit 361a357088)

# Conflicts:
#	erpnext/accounts/doctype/payment_entry/payment_entry.py

* chore: resolve conflicts

---------

Co-authored-by: Dany Robert <danyrt@wahni.com>
Co-authored-by: Deepesh Garg <deepeshgarg6@gmail.com>

erpnext/accounts/doctype/payment_entry/payment_entry.py

@@ -1336,6 +1336,9 @@ def get_outstanding_reference_documents(args):
 	if args.get("party_type") == "Member":
 		return
 
+	if not args.get("get_outstanding_invoices") and not args.get("get_orders_to_be_billed"):
+		args["get_outstanding_invoices"] = True
+
 	# confirm that Supplier is not blocked
 	if args.get("party_type") == "Supplier":
 		supplier_status = get_supplier_block_status(args["party"])
@@ -1517,22 +1520,21 @@ def get_orders_to_be_billed(
 	cost_center=None,
 	filters=None,
 ):
+	voucher_type = None
 	if party_type == "Customer":
 		voucher_type = "Sales Order"
 	elif party_type == "Supplier":
 		voucher_type = "Purchase Order"
-	elif party_type == "Employee":
-		voucher_type = None
+
+	if not voucher_type:
+		return []
 
 	# Add cost center condition
-	if voucher_type:
 	doc = frappe.get_doc({"doctype": voucher_type})
 	condition = ""
 	if doc and hasattr(doc, "cost_center") and doc.cost_center:
 		condition = " and cost_center='%s'" % cost_center
 
-	orders = []
-	if voucher_type:
 	if party_account_currency == company_currency:
 		grand_total_field = "base_grand_total"
 		rounded_total_field = "base_rounded_total"
@@ -1603,6 +1605,8 @@ def get_negative_outstanding_invoices(
 	cost_center=None,
 	condition=None,
 ):
+	if party_type not in ["Customer", "Supplier"]:
+		return []
 	voucher_type = "Sales Invoice" if party_type == "Customer" else "Purchase Invoice"
 	supplier_condition = ""
 	if voucher_type == "Purchase Invoice":