UpdateStoryListChatCount.fromJson constructor
Parse from a json
Implementation
factory UpdateStoryListChatCount.fromJson(Map<String, dynamic> json) =>
    UpdateStoryListChatCount(
      storyList: StoryList.fromJson(json['story_list']),
      chatCount: json['chat_count'],
      extra: json['@extra'],
      clientId: json['@client_id'],
    );