Allow users to change the chatbot area

[hysts]

• I have searched to see if a similar issue already exists.

Sometimes, app authors specify the height of the gr.Chatbot component, but the height may be too small and it might be hard to take good screenshots, so I think it would be useful if users can drag and expand the chat area even when the height is specified.

For example, in this Space, the height is set to 450 here, but it's definitely not enough for screenshots.

[abidlabs]

Maybe we could have the chatbot be able to pop out and take up the full screen as people have requested with Image and Gallery. It would also make the chatbot easier to use on mobile

cc @dawoodkhan82 @hannahblair