fix: incorrect discount on other item

When discount is applied on other item, don't update `discount_amount`
as the amount is calculated for current item

(cherry picked from commit 654764e)

erpnext/public/js/controllers/transaction.js

@@ -1733,6 +1733,10 @@ erpnext.TransactionController = class TransactionController extends erpnext.taxe
 				me.frm.doc.items.forEach(d => {
 					if (in_list(JSON.parse(data.apply_rule_on_other_items), d[data.apply_rule_on])) {
 						for(var k in data) {
+							if (data.pricing_rule_for == "Discount Percentage" && data.apply_rule_on_other_items && k == "discount_amount") {
+								continue;
+							}
+
 							if (in_list(fields, k) && data[k] && (data.price_or_product_discount === 'Price' || k === 'pricing_rules')) {
 								frappe.model.set_value(d.doctype, d.name, k, data[k]);
 							}