fix: key error for stock ledger report (backport #41700) (#41703)

fix: key error for stock ledger report (#41700)

(cherry picked from commit 4e37ed9)

Co-authored-by: rohitwaghchaure <rohitw1991@gmail.com>

erpnext/stock/report/stock_ledger/stock_ledger.py

@@ -67,7 +67,12 @@ def execute(filters=None):
 		if filters.get("batch_no") or inventory_dimension_filters_applied:
 			actual_qty += flt(sle.actual_qty, precision)
 			stock_value += sle.stock_value_difference
-			batch_balance_dict[sle.batch_no] += sle.actual_qty
+			if sle.batch_no:
+				if not batch_balance_dict.get(sle.batch_no):
+					batch_balance_dict[sle.batch_no] = 0
+
+				batch_balance_dict[sle.batch_no] += sle.actual_qty
+
 			if filters.get("segregate_serial_batch_bundle"):
 				actual_qty = batch_balance_dict[sle.batch_no]