[Enhancement][ESS] Add a note in Manage detection alerts -> Edit drop…

…-down filter controls (#5003)

* First draft

* Minor tweaks

* Update docs/detections/alerts-ui-manage.asciidoc

* Fixing broken ref

(cherry picked from commit 5d787a7)

docs/detections/alerts-ui-manage.asciidoc

@@ -59,7 +59,8 @@ image::images/alert-page-dropdown-controls.png[Alerts page with drop-down contro
 ====
 * You can have a maximum of four controls on the Alerts page.
 * You can't remove the *Status* control.
-* If you make any changes to the controls, you _must_ save the pending changes for them to persist.
+* If you make any changes to the controls, you _must_ save the pending changes for them to persist. 
+* Saved changes are stored in your browser's local storage, not your {ref}/user-profile.html[user profile]. If you clear your browser's storage or log into your user profile from a different browser, you will lose your customizations.
 ====
 
 . Click the three-dot icon next to the controls (image:images/three-dot-icon-blue.png[Three-dot icon,18,18]), then select *Edit Controls*.