Add 1 changelog entries for Team:Core/Infra

Author: georgewallace

release-notes/elastic-cloud-serverless/index.md

@@ -66,6 +66,7 @@ Review the changes, fixes, and more to {{serverless-full}}.
 * Speeds up field simulation in Streams [#241313]({{kib-pull}}241313)
 * Updates action response codes [#240420]({{kib-pull}}240420)
 * Fixes an infinite loop bug in the **Investigation guide** editor [#240472]({{kib-pull}}240472)
+* cat API: added endpoint for Circuit Breakers [#136890](https://github.com/elastic/elasticsearch/pull/136890)
 
 ## October 27, 2025 [serverless-changelog-10272025]