Accessibility issue if `<Layout />` component has overflow and 0 focusable children (sighted keyboard users are unable to scroll the layout region)

We should revisit how this layout container works and potentially move back to the more simple approach of allowing the body to have overflow.

Background on this decision was that we wanted to avoid the browser allowing things to be in focus behind our topbar. By default, the browser will minimally scroll a focused element into "view" but as far as the browser is concerned, being behind the topbar is in "view"