Topics with n/a message count first

Author: germanosin

api/src/main/java/io/kafbat/ui/controller/TopicsController.java

@@ -363,7 +363,7 @@ private Comparator<InternalTopic> getComparatorForTopic(
       case SIZE -> Comparator.comparing(InternalTopic::getSegmentSize);
       case MESSAGES_COUNT ->  Comparator.comparing(
           InternalTopic::getMessagesCount,
-          Comparator.nullsLast(Long::compareTo)
+          Comparator.nullsFirst(Long::compareTo)
       );
       default -> defaultComparator;
     };