removed unused import

Signed-off-by: Peter Alfonsi <[email protected]>

Author: Peter Alfonsi

plugins/cache-ehcache/src/test/java/org/opensearch/cache/store/disk/EhCacheDiskCacheTests.java

@@ -48,8 +48,6 @@
 import java.util.concurrent.Phaser;
 import java.util.function.ToLongBiFunction;
 
-import org.ehcache.impl.serialization.StringSerializer;
-
 import static org.opensearch.cache.EhcacheDiskCacheSettings.DISK_LISTENER_MODE_SYNC_KEY;
 import static org.opensearch.cache.EhcacheDiskCacheSettings.DISK_MAX_SIZE_IN_BYTES_KEY;
 import static org.opensearch.cache.EhcacheDiskCacheSettings.DISK_STORAGE_PATH_KEY;