[Hotfix][Connector-V2] Release resources when task is closed for iceb…

…erg sinkwriter (apache#7729)

seatunnel-connectors-v2/connector-iceberg/src/main/java/org/apache/seatunnel/connectors/seatunnel/iceberg/sink/IcebergSinkWriter.java

@@ -146,7 +146,15 @@ public List<IcebergSinkState> snapshotState(long checkpointId) throws IOExceptio
     public void abortPrepare() {}
 
     @Override
-    public void close() throws IOException {}
+    public void close() throws IOException {
+        try {
+            if (writer != null) {
+                writer.close();
+            }
+        } finally {
+            results.clear();
+        }
+    }
 
     private String fieldsInfo(SeaTunnelRowType seaTunnelRowType) {
         String[] fieldsInfo = new String[seaTunnelRowType.getTotalFields()];