fix: correct doctype in item_wise_purchase register

(cherry picked from commit b8b8dce733)

erpnext/accounts/report/item_wise_purchase_register/item_wise_purchase_register.py

@@ -369,7 +369,7 @@ def get_items(filters, additional_table_columns):
 	from frappe.desk.reportview import build_match_conditions
 
 	query, params = query.walk()
-	match_conditions = build_match_conditions("Sales Invoice")
+	match_conditions = build_match_conditions(doctype)
 
 	if match_conditions:
 		query += " and " + match_conditions