Improve /try-matrix mobile layout with banner enabled

Despite our best efforts to put exactly the "tldr" all in the initial view, the banner means the content is pushed down so far that the CTA is not reachable without scrolling. We should consider how to solve this best.

Start by locating the /try-matrix page and its mobile layout and banner entry points. Reproduce the page with the banner enabled at a mobile viewport, then verify that the initial view still presents the tldr and makes the CTA reachable without scrolling.

Written by the indexing model from the issue text.