fix: remove catch-all handler for unknown commands

Unknown commands like /asdasda no longer show help.
Only known commands (with explicit handlers) respond.

apps/telegram-bot/bot.py

@@ -67,8 +67,6 @@ def build_app() -> Application:
 
     app.add_handler(CallbackQueryHandler(cmd_delete_message))
 
-    app.add_handler(MessageHandler(filters.COMMAND, cmd_help))
-
     app.add_error_handler(error_handler)
 
     return app