Add Query Insights excluded_indices section (opensearch-project#10011)

* Add Query Insights excluded_indices section

Signed-off-by: David Zane <[email protected]>

* Update _observing-your-data/query-insights/top-n-queries.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: David Zane <[email protected]>

* Update _observing-your-data/query-insights/top-n-queries.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: David Zane <[email protected]>

* Update _observing-your-data/query-insights/top-n-queries.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: David Zane <[email protected]>

* Apply suggestions from code review

Signed-off-by: kolchfa-aws <[email protected]>

---------

Signed-off-by: David Zane <[email protected]>
Signed-off-by: David Zane <[email protected]>
Signed-off-by: kolchfa-aws <[email protected]>
Co-authored-by: kolchfa-aws <[email protected]>

Author: dzane17

_observing-your-data/query-insights/top-n-queries.md

@@ -334,3 +334,21 @@ PUT _cluster/settings
 }
 ```
 {% include copy-curl.html %}
+
+## Excluding indexes from top N queries
+
+You can exclude search queries from the top N query list based on the indexes they target. This is useful when certain indexes are known to have long-running queries and don't need to be monitored.
+
+A query is excluded if it searches any shard that belongs to an index listed in `excluded_indices`.
+
+By default, this setting is `null` (all indexes are included). To exclude specific indexes, provide a comma-separated list of index names in the `search.insights.top_queries.excluded_indices` setting:
+
+```json
+PUT _cluster/settings
+{
+  "persistent" : {
+    "search.insights.top_queries.excluded_indices" : "index-1,index-2,index-3"
+  }
+}
+```
+{% include copy-curl.html %}