for last message in conversation list: indicate thread

if the last message in a chat was posted in a thread, the conversation list will show it at last message, but there is no indicator if it was in a thread. 
When opening the chat users might be confused where the message is.

We need to show a thread icon like in web:

<img width="400" height="308" alt="Image" src="https://github.com/user-attachments/assets/34844356-d7db-4004-ab58-25f6713b3ea2" />