Fixes checkstyle errors

Signed-off-by: Darshit Chanpura <dchanp@amazon.com>

Author: DarshitChanpura

src/test/java/org/opensearch/security/resources/ResourceAccessHandlerTest.java

@@ -35,7 +35,7 @@
 import org.opensearch.security.user.User;
 import org.opensearch.threadpool.ThreadPool;
 
-import org.mockito.*;
+import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
 
 import static org.mockito.Mockito.any;