UX: Add second Search button on mobile (PR #14404)

On mobile, when the advanced options are expanded in the full page search UI, it’s useful to have a second button so users don’t have to scroll back up.


I know you didn’t introduce this, but I dislike boolean parameters like this that aren’t named. I have no idea what true represents from reading it. Maybe if we have time we can circle back and changed it to a something=true parameter?