[improve] add ckptid in label when 2pc false (#207)

Currently, when 2pc is closed, the label will only splice the uuid without adding the ckid, which is inconvenient to locate the problem.
diff --git a/flink-doris-connector/src/main/java/org/apache/doris/flink/sink/writer/LabelGenerator.java b/flink-doris-connector/src/main/java/org/apache/doris/flink/sink/writer/LabelGenerator.java
index 35edae9..235b553 100644
--- a/flink-doris-connector/src/main/java/org/apache/doris/flink/sink/writer/LabelGenerator.java
+++ b/flink-doris-connector/src/main/java/org/apache/doris/flink/sink/writer/LabelGenerator.java
@@ -31,7 +31,8 @@
     }
 
     public String generateLabel(long chkId) {
-        return enable2PC ? labelPrefix + "_" + chkId : labelPrefix + "_" + UUID.randomUUID();
+        String label = labelPrefix + "_" + chkId;
+        return enable2PC ? label : label + "_" + UUID.randomUUID();
     }
 
     public String generateBatchLabel() {