Update main.py

Co-authored-by: Eugene Evstafev <36392751+chigwell@users.noreply.github.com>

main.py

@@ -944,7 +944,7 @@ async def list_chats(chat_type: str = None, limit: int = 20) -> str:
             # Also check unread_mark (manual "mark as unread" flag)
             inner_dialog = getattr(dialog, "dialog", None)
             unread_mark = (
-                getattr(dialog.dialog, "unread_mark", False)
+                getattr(inner_dialog, "unread_mark", False))
                 if hasattr(dialog, "dialog")
                 else False
             )