docs: Migrate notification-update to notifications docs

Bug: 30224465
Change-Id: I43ded785db6c69d493965f50f798262595b2d026
diff --git a/docs/html/_redirects.yaml b/docs/html/_redirects.yaml
index 7d7282db..0dd1c89 100644
--- a/docs/html/_redirects.yaml
+++ b/docs/html/_redirects.yaml
@@ -1216,3 +1216,5 @@
   to: /training/articles/direct-boot.html
 - from: /preview/features/scoped-folder-access.html
   to: /training/articles/scoped-directory-access.html
+- from: /preview/features/notification-updates.html
+  to: /guide/topics/ui/notifiers/notifications.html