Fix notification list bugs (#25781)

Fix #25627

1. `ctx.Data["Link"]` should use relative URL but not AppURL
2. The `data-params` is incorrect because it doesn't contain "page". JS
can simply use "window.location.search" to construct the AJAX URL
3. The `data-xxx` and `id` in notification_subscriptions.tmpl were
copied&pasted, they don't have affect.

web_src/js/features/notification.js

@@ -165,7 +165,7 @@ async function updateNotificationTable() {
   if (notificationDiv.length > 0) {
     const data = await $.ajax({
       type: 'GET',
-      url: `${appSubUrl}/notifications?${notificationDiv.data('params')}`,
+      url: `${appSubUrl}/notifications${window.location.search}`,
       data: {
         'div-only': true,
         'sequence-number': ++notificationSequenceNumber,