Fix a bug

Signed-off-by: bowenlan-amzn <[email protected]>

server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregator.java

@@ -183,6 +183,7 @@ protected boolean canOptimize() {
 
                     // bucketOrds is used for saving the date histogram results got from the optimization path
                     bucketOrds = LongKeyedBucketOrds.build(context.bigArrays(), CardinalityUpperBound.ONE);
+                    return true;
                 }
                 return false;
             }