fix: Set barcode field empty only if it has value (#21425)

- To avoid unnecessary form dirty trigger
diff --git a/erpnext/public/js/controllers/transaction.js b/erpnext/public/js/controllers/transaction.js
index 4296447..5843034 100644
--- a/erpnext/public/js/controllers/transaction.js
+++ b/erpnext/public/js/controllers/transaction.js
@@ -288,7 +288,7 @@
 		this.setup_sms();
 		this.setup_quality_inspection();
 		let scan_barcode_field = this.frm.get_field('scan_barcode');
-		if (scan_barcode_field) {
+		if (scan_barcode_field && scan_barcode_field.get_value()) {
 			scan_barcode_field.set_value("");
 			scan_barcode_field.set_new_description("");