fix: buying rate for service item in gross profit report

(cherry picked from commit 8d6e79a16f)

erpnext/accounts/report/gross_profit/gross_profit.py

@@ -726,12 +726,13 @@ class GrossProfitGenerator:
 			.inner_join(purchase_invoice)
 			.on(purchase_invoice.name == purchase_invoice_item.parent)
 			.select(
-				purchase_invoice.name,
 				purchase_invoice_item.base_rate / purchase_invoice_item.conversion_factor,
 			)
 			.where(purchase_invoice.docstatus == 1)
 			.where(purchase_invoice.posting_date <= self.filters.to_date)
 			.where(purchase_invoice_item.item_code == item_code)
+			.where(purchase_invoice.is_return == 0)
+			.where(purchase_invoice_item.parenttype == "Purchase Invoice")
 		)
 
 		if row.project: