[hotfix] remove redundant "wait" for CompletableFuture (#657)

---------

Co-authored-by: yuxia Luo <luoyuxia@alumni.sjtu.edu.cn>

Author: zcoo

fluss-server/src/main/java/com/alibaba/fluss/server/log/LogTablet.java

@@ -456,7 +456,7 @@ public void updateRemoteLogEndOffset(long remoteLogEndOffset) {
         if (remoteLogEndOffset > this.remoteLogEndOffset) {
             this.remoteLogEndOffset = remoteLogEndOffset;
 
-            // try to delete these segments already exits in remote storage.
+            // try to delete these segments already exist in remote storage.
             deleteSegmentsAlreadyExistsInRemote();
         }
     }

fluss-server/src/main/java/com/alibaba/fluss/server/log/remote/DefaultRemoteLogStorage.java

@@ -105,9 +105,6 @@ public void copyLogSegmentFiles(
             List<CompletableFuture<Void>> futures =
                     createUploadFutures(remoteLogSegment, logSegmentFiles);
             FutureUtils.waitForAll(futures).get();
-            for (CompletableFuture<Void> future : futures) {
-                future.get();
-            }
         } catch (ExecutionException e) {
             Throwable throwable = ExceptionUtils.stripExecutionException(e);
             throwable = ExceptionUtils.stripException(throwable, RuntimeException.class);