Gutenboarding: fix confusing keyboard focus / mouse hover states

[simison]

When landing at page selector, the first item has "focus" by default and it thus gets focus styles (dark border):

When I now hover with mouse anything else on this page, they also get hover state:

Once I select something, things look good again:

I would expect to see the initial focus state be visible only when I'm keyboard navigating. I think we use accessible-focus elsewhere to show keyboard focus only when tabbing with keyboard, but there could be some more simple solution as well.

[Addison-Stavlo]

My apologies if I am stepping on any toes here.

I was looking into #38665 and noticed this lingering-focus problem while I was working on that. I went ahead with trying to fix it before I saw this issue had some folks assigned already. Im going to go ahead and open this small PR for it, but feel free to take it over or make any changes you see fit if desired.

Again, sorry for jumping onto the already assigned issue.