[hotfix] Add isClosed protect for LogFetcher#handleFetchLogException to avoid throw exception if channel close (#1107)

Author: swuferhong

fluss-client/src/main/java/com/alibaba/fluss/client/table/scanner/log/LogFetcher.java

@@ -272,6 +272,10 @@ private void invalidTableOrPartitions(TableOrPartitions tableOrPartitions) {
     private void handleFetchLogException(
             int destination, TableOrPartitions tableOrPartitionsInFetchRequest, Throwable e) {
         try {
+            if (isClosed) {
+                return;
+            }
+
             LOG.error("Failed to fetch log from node {}", destination, e);
             // if is invalid metadata exception, we need to clear table bucket meta
             // to enable another round of log fetch to request new medata