fix: fetch appointment letter content in the same order as template (#28968)

diff --git a/erpnext/hr/doctype/appointment_letter/appointment_letter.py b/erpnext/hr/doctype/appointment_letter/appointment_letter.py
index 0120188..71327bf 100644
--- a/erpnext/hr/doctype/appointment_letter/appointment_letter.py
+++ b/erpnext/hr/doctype/appointment_letter/appointment_letter.py
@@ -12,14 +12,15 @@
 @frappe.whitelist()
 def get_appointment_letter_details(template):
 	body = []
-	intro= frappe.get_list("Appointment Letter Template",
-		fields = ['introduction', 'closing_notes'],
-		filters={'name': template
-	})[0]
-	content = frappe.get_list("Appointment Letter content",
-		fields = ['title', 'description'],
-		filters={'parent': template
-	})
+	intro = frappe.get_list('Appointment Letter Template',
+		fields=['introduction', 'closing_notes'],
+		filters={'name': template}
+	)[0]
+	content = frappe.get_all('Appointment Letter content',
+		fields=['title', 'description'],
+		filters={'parent': template},
+		order_by='idx'
+	)
 	body.append(intro)
 	body.append({'description': content})
 	return body