How to disable "Hide message after" on the Slide-in?

Hi, I'd like to turn off the "Hide message after" so that the slide-in doesn't disappear unless "close" is clicked. The slide-in we have contains a form, and even 59 seconds may not be enough time for people to fill it out, so I need it disabled altogether. How can I do this? I'm a developer so I understand code snippets! Thanks!