Updates 9.0 breaking changes with ES|QL item. (#128038)

Author: szabosteve

docs/release-notes/breaking-changes.md

@@ -39,6 +39,9 @@ will prevent node from starting [#118366](https://github.com/elastic/elasticsear
 Cluster Coordination:
 * Remove unsupported legacy value for `discovery.type` [#112903](https://github.com/elastic/elasticsearch/pull/112903)
 
+ES|QL
+* Limit the scope of the skip_unavailable setting for remote clusters [#120236](https://github.com/elastic/elasticsearch/pull/120236)
+
 EQL:
 * Set allow_partial_search_results=true by default [#120267](https://github.com/elastic/elasticsearch/pull/120267)