[flink] fix de-merge-into runtimeContext may throw NoSuchMethod error (#7607)

Author: steFaiz

paimon-flink/paimon-flink-common/src/main/java/org/apache/paimon/flink/dataevolution/MergeIntoUpdateChecker.java

@@ -23,6 +23,7 @@
 import org.apache.paimon.data.BinaryRow;
 import org.apache.paimon.flink.sink.Committable;
 import org.apache.paimon.flink.utils.BoundedOneInputOperator;
+import org.apache.paimon.flink.utils.RuntimeContextUtils;
 import org.apache.paimon.index.GlobalIndexMeta;
 import org.apache.paimon.index.IndexFileMeta;
 import org.apache.paimon.io.CompactIncrement;
@@ -70,7 +71,7 @@ public void open() throws Exception {
         affectedPartitions = new HashSet<>();
 
         Preconditions.checkState(
-                getRuntimeContext().getTaskInfo().getNumberOfParallelSubtasks() == 1,
+                RuntimeContextUtils.getNumberOfParallelSubtasks(getRuntimeContext()) == 1,
                 "Parallelism of MergeIntoUpdateChecker must be 1.");
     }