Replace autodevops illustrations with devops-sm

What does this MR do and why?

Replace old autodevops illustration with the new devops-sm

Screenshots or screen recordings

Before	After

How to set up and validate locally

I don't know how to make this banner visible, but I see it on some personal projects, for example, https://gitlab.com/jmiocene/theme-tests.

1. Open app/helpers/auto_devops_helper.rb
2. Replace show_auto_devops_callout block with

       def show_auto_devops_callout?(project)
           return true
       end

3. Go to any empty or new project
4. See the banner

#430246 (closed)