fix: map tax table while creating purchase order from sales order

(cherry picked from commit 1e18569be7)

erpnext/selling/doctype/sales_order/sales_order.py

@@ -1427,6 +1427,8 @@ def make_purchase_order(source_name, selected_items=None, target_doc=None):
 			target.customer = target.customer_name = target.shipping_address = None
 
 		target.run_method("set_missing_values")
+		if not target.taxes:
+			target.append_taxes_from_item_tax_template()
 		target.run_method("calculate_taxes_and_totals")
 
 	def update_item(source, target, source_parent):