chore: remove outdated TODO

Author: ronjaquensel

src/main/java/org/eclipse/dataplane/domain/dataflow/DataFlow.java

@@ -22,7 +22,6 @@
 import java.util.Map;
 import java.util.Objects;
 
-// TODO: could it store the messages?
 public class DataFlow {
 
     private String id;