fix: compute modal title server side

(cherry picked from commit 33d59d6)

frappe/templates/includes/contact.js

@@ -29,7 +29,7 @@ frappe.ready(function() {
 			message: message,
 			callback: function(r) {
 				if (!r.exc) {
-					frappe.msgprint('{{ _("Thank you for your message") }}');
+					frappe.msgprint('{{ _("Thank you for your message") }}', '{{ _("Message Sent") }}');
 				}
 				$(':input').val('');
 			}