Support disabling mo.ui.chat input

[aszenz]

Description

I was hoping to make my chatbot disabled until the user entered an api key in another input but didn't see any parameter to disable the input.

Suggested solution

Support disabled parameter on the Chat input.

When set to true it can create a non interactive overlay over the input.

Html now supports inert attribute to disable interactions inside an element. Inert elements can be styled to achieve the disabled styling.

See: https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/inert

Alternative

Currently using mo.stop to not show the cell at all.

Additional context

Here's the notebook where I want to use this:

https://aszenz.github.io/kashmiri-chatbot/

By not showing the input, I have a feeling people won't understand how the chatbot looks like.