Make error code clickable on Duo Chat

On Duo Chat, we need to make the error code clickable. It should link to this page.

However, in order to do this, the error response needs to support markdown.

Note that the prompt from the user supports markdown, but not the error div.

How to reproduce locally

It is tricky to reproduce without forcing an error, and also making the error a link.

1. Apply this patch
2. Ask Duo Chat any question