Adding this obo config to xcontent builder and remove unused imports

Signed-off-by: Ryan Liang <jiallian@amazon.com>

Author: RyanL1997

src/integrationTest/java/org/opensearch/test/framework/TestSecurityConfig.java

@@ -221,6 +221,10 @@ public XContentBuilder toXContent(XContentBuilder xContentBuilder, Params params
 			xContentBuilder.startObject();
 			xContentBuilder.startObject("dynamic");
 
+			if (onBehalfOfConfig != null) {
+				xContentBuilder.field("on_behalf_of", onBehalfOfConfig);
+			}
+
 			if (anonymousAuth || (xffConfig != null)) {
 				xContentBuilder.startObject("http");
 				xContentBuilder.field("anonymous_auth_enabled", anonymousAuth);

src/main/java/org/opensearch/security/http/HTTPOnBehalfOfJwtAuthenticator.java

@@ -32,7 +32,6 @@
 import org.apache.hc.core5.http.HttpHeaders;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.greenrobot.eventbus.Subscribe;
 
 import org.opensearch.OpenSearchSecurityException;
 import org.opensearch.SpecialPermission;
@@ -42,7 +41,6 @@
 import org.opensearch.rest.RestRequest;
 import org.opensearch.security.auth.HTTPAuthenticator;
 import org.opensearch.security.authtoken.jwt.EncryptionDecryptionUtil;
-import org.opensearch.security.securityconf.DynamicConfigModel;
 import org.opensearch.security.user.AuthCredentials;
 
 public class HTTPOnBehalfOfJwtAuthenticator implements HTTPAuthenticator {