feat: get_valuation_rate batch wise

This function is used to show valuation rate on frontend and also as
fallback in case values aren't available. Add "batch_no" param to get
batch specific valuation rates.

Co-Authored-By: Alan Tom <2.alan.tom@gmail.com>
diff --git a/erpnext/controllers/buying_controller.py b/erpnext/controllers/buying_controller.py
index a181af7..b831557 100644
--- a/erpnext/controllers/buying_controller.py
+++ b/erpnext/controllers/buying_controller.py
@@ -249,6 +249,7 @@
 						"posting_time": self.get('posting_time'),
 						"qty": -1 * flt(d.get('stock_qty')),
 						"serial_no": d.get('serial_no'),
+						"batch_no": d.get("batch_no"),
 						"company": self.company,
 						"voucher_type": self.doctype,
 						"voucher_no": self.name,