"Am not A Robot" - possible in the bot?

Is there any feature or possibility through which users can be validated to not be a robot?

You can try adding reCAPTCHA through image node.
If you can define what exact method out of accepted methods to check humans you want to integrate, we can help you more.

Looping in @akshay_bhat from widget team to see if we have any generic way to do so integrated.

Namaste @Shrestha_Ganguly
We do not have a way to conduct verification within the bot. An alternate approach would be to set up authentication based bot access, so that users can access the bot post authentication on host website/app.