feat: add closed by and closer on livechat ILivechatRoom (#795)

Author: ggazzo

src/definition/livechat/ILivechatRoom.ts

@@ -37,6 +37,8 @@ export interface ILivechatRoom extends IRoom {
     visitor: IVisitor;
     visitorChannelInfo?: IVisitorChannelInfo;
     department?: IDepartment;
+    closer: 'user' | 'visitor' | 'bot';
+    closedBy?: IUser;
     servedBy?: IUser;
     responseBy?: IUser;
     isWaitingResponse: boolean;