[opt-36803][file] Adjust fileSource Metric wait time to 20s.

Author: FlechazoW

file/file-source/src/main/java/com/dtstack/flink/sql/source/file/FileSource.java

@@ -62,7 +62,7 @@
 public class FileSource extends AbstractRichFunction implements IStreamSourceGener<Table>, SourceFunction<Row> {
     private static final Logger LOG = LoggerFactory.getLogger(FileSource.class);
 
-    private static final Long METRIC_WAIT_TIME = 5L;
+    private static final Long METRIC_WAIT_TIME = 20L;
 
     private static final String SP = File.separator;