fix checkstyle violation

Author: polyzos

fluss-client/src/main/java/org/apache/fluss/client/lookup/Lookuper.java

@@ -18,7 +18,6 @@
 package org.apache.fluss.client.lookup;
 
 import org.apache.fluss.annotation.PublicEvolving;
-import org.apache.fluss.row.InternalRow;
 
 import java.util.concurrent.CompletableFuture;