fix(checkstyle): eventmesh-connector-file EmptyLineSeparator + NeedBraces

Author: qqeasonchen

eventmesh-connector-plugin/eventmesh-connector-file/src/main/java/org/apache/eventmesh/connector/file/sink/FileSinkConnector.java

@@ -31,6 +31,7 @@
 public class FileSinkConnector implements SinkConnector {
 
     private java.io.PrintStream out;
+
     @Override
     public void init(Properties props) {
         try {
@@ -39,6 +40,7 @@ public void init(Properties props) {
             throw new RuntimeException(e);
         }
     }
+
     @Override
     public void put(List<CloudEvent> events) {
         for (CloudEvent event : events) {
@@ -47,6 +49,7 @@ public void put(List<CloudEvent> events) {
         }
         out.flush();
     }
+
     @Override
     public void commit(List<CloudEvent> written) {
 

eventmesh-connector-plugin/eventmesh-connector-file/src/main/java/org/apache/eventmesh/connector/file/source/FileSourceConnector.java

@@ -35,6 +35,7 @@
 public class FileSourceConnector implements SourceConnector {
 
     private java.io.BufferedReader reader;
+
     @Override
     public void init(Properties props) {
         try {
@@ -43,10 +44,12 @@ public void init(Properties props) {
             throw new RuntimeException(e);
         }
     }
+
     @Override
     public List<CloudEvent> poll() {
-        if (reader == null)
+        if (reader == null) {
             return Collections.emptyList();
+        }
         List<CloudEvent> out = new ArrayList<>();
         try {
             String line;
@@ -61,6 +64,7 @@ public List<CloudEvent> poll() {
         }
         return out;
     }
+
     @Override
     public void commit(CloudEvent lastPublished) {