Changed CatShardsAction to internal to allow non-admin users

Signed-off-by: Somesh Gupta <guptasom@amazon.com>

Author: guptasom

CHANGELOG.md

@@ -124,6 +124,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Fix AutoDateHistogramAggregator rounding assertion failure ([#17023](https://github.com/opensearch-project/OpenSearch/pull/17023))
 - Add highlighting for wildcard search on `match_only_text` field ([#17101](https://github.com/opensearch-project/OpenSearch/pull/17101))
 - Fix the failing CI's with `Failed to load eclipse jdt formatter` error ([#17172](https://github.com/opensearch-project/OpenSearch/pull/17172))
+- Changed CatShardsAction to internal to allow non-admin users. ([#17203](https://github.com/opensearch-project/OpenSearch/pull/17203))
 
 ### Security
 

server/src/main/java/org/opensearch/action/admin/cluster/shards/CatShardsAction.java

@@ -17,7 +17,7 @@
  */
 public class CatShardsAction extends ActionType<CatShardsResponse> {
     public static final CatShardsAction INSTANCE = new CatShardsAction();
-    public static final String NAME = "cluster:monitor/shards";
+    public static final String NAME = "internal:monitor/shards";
 
     private CatShardsAction() {
         super(NAME, CatShardsResponse::new);