Fix BlockTransferManagerTests to extend OpenSearchTestCase instead of LuceneTestCase (#21363)

BlockTransferManagerTests was extending LuceneTestCase directly which causes
sysout check failures since the test uses loggers that print to console.
Changed to extend OpenSearchTestCase which already includes
@SuppressSysoutChecks and follows the project convention for all server tests.

Signed-off-by: Mayank Harsh <mayankmh@amazon.com>
Co-authored-by: Mayank Harsh <mayankmh@amazon.com>

Author: MayankHarsh03

server/src/test/java/org/opensearch/storage/common/BlockTransferManagerTests.java

@@ -12,7 +12,6 @@
 
 import org.apache.lucene.store.FSDirectory;
 import org.apache.lucene.store.IOContext;
-import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.UUIDs;
@@ -23,6 +22,7 @@
 import org.opensearch.index.store.remote.utils.TransferManager;
 import org.opensearch.node.Node;
 import org.opensearch.storage.indexinput.BlockFetchRequest;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.junit.After;
 import org.junit.Assert;
@@ -52,7 +52,7 @@
  * Tests cover single block downloads, failure scenarios, duplicate handling, and concurrent operations.
  */
 @ThreadLeakFilters(filters = CleanerDaemonThreadLeakFilter.class)
-public class BlockTransferManagerTests extends LuceneTestCase {
+public class BlockTransferManagerTests extends OpenSearchTestCase {
 
     // Node and index configuration constants
     private static final String TEST_NODE_NAME = "test-node";