fix(ux): get items on selecting DN in Packing Slip

(cherry picked from commit e75aa4e)

erpnext/stock/doctype/packing_slip/packing_slip.js

@@ -1,7 +1,7 @@
 // Copyright (c) 2023, Frappe Technologies Pvt. Ltd. and contributors
 // For license information, please see license.txt
 
-frappe.ui.form.on("Packing Slip", {
+frappe.ui.form.on('Packing Slip', {
     setup: (frm) => {
         frm.set_query('delivery_note', () => {
             return {
@@ -13,7 +13,7 @@ frappe.ui.form.on("Packing Slip", {
 
         frm.set_query('item_code', 'items', (doc, cdt, cdn) => {
             if (!doc.delivery_note) {
-                frappe.throw(__("Please select a Delivery Note"));
+                frappe.throw(__('Please select a Delivery Note'));
             } else {
                 let d = locals[cdt][cdn];
                 return {
@@ -27,6 +27,20 @@ frappe.ui.form.on("Packing Slip", {
 	},
 
 	refresh: (frm) => {
-		frm.toggle_display("misc_details", frm.doc.amended_from);
-	}
+		frm.toggle_display('misc_details', frm.doc.amended_from);
+	},
+
+	delivery_note: (frm) => {
+		frm.set_value('items', null);
+
+		if (frm.doc.delivery_note) {
+			erpnext.utils.map_current_doc({
+				method: 'erpnext.stock.doctype.delivery_note.delivery_note.make_packing_slip',
+				source_name: frm.doc.delivery_note,
+				target_doc: frm,
+				freeze: true,
+				freeze_message: __('Creating Packing Slip ...'),
+			});
+		}
+	},
 });