fix(patch): sle.serial_no = "\n" causes incorrect queue (#29306)

This happens due to old data.
diff --git a/erpnext/stock/stock_ledger.py b/erpnext/stock/stock_ledger.py
index 44e70a4..262aa81 100644
--- a/erpnext/stock/stock_ledger.py
+++ b/erpnext/stock/stock_ledger.py
@@ -105,6 +105,7 @@
 
 def validate_serial_no(sle):
 	from erpnext.stock.doctype.serial_no.serial_no import get_serial_nos
+
 	for sn in get_serial_nos(sle.serial_no):
 		args = copy.deepcopy(sle)
 		args.serial_no = sn
@@ -423,6 +424,8 @@
 		return sorted(entries_to_fix, key=lambda k: k['timestamp'])
 
 	def process_sle(self, sle):
+		from erpnext.stock.doctype.serial_no.serial_no import get_serial_nos
+
 		# previous sle data for this warehouse
 		self.wh_data = self.data[sle.warehouse]
 
@@ -437,7 +440,7 @@
 		if not self.args.get("sle_id"):
 			self.get_dynamic_incoming_outgoing_rate(sle)
 
-		if sle.serial_no:
+		if get_serial_nos(sle.serial_no):
 			self.get_serialized_values(sle)
 			self.wh_data.qty_after_transaction += flt(sle.actual_qty)
 			if sle.voucher_type == "Stock Reconciliation":