Updated CHANGELOG.md & fixed format violation

Author: Karthik Subramanian

CHANGELOG.md

@@ -32,6 +32,7 @@ This section is for maintaining a changelog for all breaking changes for the cli
 ### Dependencies
 
 ### Changed
+- Allow null values in arrays ([#679](https://github.com/opensearch-project/opensearch-java/pull/679))
 
 ### Deprecated
 

java-client/src/test/java/org/opensearch/client/opensearch/json/JsonpDeserializerBaseTest.java

@@ -1,15 +1,13 @@
 package org.opensearch.client.opensearch.json;
 
 import jakarta.json.stream.JsonParser;
+import java.io.StringReader;
+import java.util.List;
 import org.junit.Test;
 import org.opensearch.client.json.JsonpDeserializer;
 import org.opensearch.client.opensearch._types.FieldValue;
 import org.opensearch.client.opensearch.model.ModelTestCase;
 
-import java.io.StringReader;
-import java.util.List;
-
-
 public class JsonpDeserializerBaseTest extends ModelTestCase {
 
     @Test