docs(service-worker): note about isStable/setInterval (#28102)

The docs don't mention that the app will never be stable if a `setInterval` is running somewhere, and that it will prevent the servcie worker to be registered too.

PR Close #28102

aio/content/guide/service-worker-communications.md

@@ -50,6 +50,9 @@ script will never be registered with the browser.
 You can avoid that by waiting for the app to stabilize first, before starting to poll for updates
 (as shown in the example above).
 
+Note that this is true for any kind of polling done by your application.
+Check the {@link ApplicationRef#isStable isStable} documentation for more information. 
+
 </div>
 
 ### Forcing update activation