Adjust index replicas settings to keep consistent with AOS 2.9 (#1325) (#1327)

Signed-off-by: Sicheng Song <[email protected]>
(cherry picked from commit ad078ff)

Co-authored-by: Sicheng Song <[email protected]>

Author: opensearch-trigger-bot[bot]

plugin/src/main/java/org/opensearch/ml/indices/MLIndicesHandler.java

@@ -37,7 +37,7 @@ public class MLIndicesHandler {
 
     ClusterService clusterService;
     Client client;
-    private static final Map<String, Object> indexSettings = Map.of("index.auto_expand_replicas", "0-5");
+    private static final Map<String, Object> indexSettings = Map.of("index.auto_expand_replicas", "0-1");
     private static final Map<String, AtomicBoolean> indexMappingUpdated = new HashMap<>();
 
     static {