Option for chat visitors to close the chatbot conversation themselves

As it is now, there is no way for a chat visitors to close the chat, instead of either waiting in the middle of a chat flow without reaching an end of path, or getting redirected to our inbox when it isn't necessary or if they have found the answer before we could respond.

This is especially inconvenient as there is currently no way to redirect the client to restart and/or go back in chatbot flow (vote for this feature here!)