lastMessage in chat (#1606)

* lastMessage in chat

* lastMessage info

* Update src/util/Injected.js

Co-authored-by: Rajeh Taher <rajeh@reforward.dev>

* fix  serialize msg

* markup

---------

Co-authored-by: tofers <tofers90>
Co-authored-by: Rajeh Taher <rajeh@reforward.dev>

index.d.ts

@@ -1038,6 +1038,8 @@ declare namespace WAWebJS {
         timestamp: number,
         /** Amount of messages unread */
         unreadCount: number,
+        /** Last message fo chat */
+        lastMessage: Message,
 
         /** Archives this chat */
         archive: () => Promise<void>,