api [nfc]: Reorder streamId and topic properties of UnreadStreamSnapshot

Author: sirpengi

lib/api/model/initial_snapshot.dart

@@ -275,13 +275,13 @@ class UnreadDmSnapshot {
 /// An item in [UnreadMessagesSnapshot.streams].
 @JsonSerializable(fieldRename: FieldRename.snake)
 class UnreadStreamSnapshot {
-  final String topic;
   final int streamId;
+  final String topic;
   final List<int> unreadMessageIds;
 
   UnreadStreamSnapshot({
-    required this.topic,
     required this.streamId,
+    required this.topic,
     required this.unreadMessageIds,
   }) : assert(isSortedWithoutDuplicates(unreadMessageIds));