fix(replays): make link copy button accessible and non-variable width

[JoshuaKGoldberg]

Fixes two issues with the replay link copy button:

• Accessibility: adds focus-within for its hover presence so non-mouse (e.g. keyboard) users can see it
• Width: keeps it in the page but with zero opacity, so it move the Update button when hovered

Also removes an extra <Flex> container around the flex container.

[JoshuaKGoldberg]

[Question] Do we, have a better way of doing this? Note the need to ${HoverArea} a few lines later.

[nsdeschenes]

I wonder if this is a legacy button setup before scraps 🤔

Wonder if we could use something like a transparent button here?

Tho maybe i'm not fully understanding why we're overriding the opacity like this.

[JoshuaKGoldberg]

This is a transparent button variant already :c

I'll ask in design-engineering, agreed it does feel kind of legacy/spooky...

[nsdeschenes]

Booooo :/

[github-actions]

📊 Type Coverage Diff

✅ No new type safety issues introduced. Coverage: 93.52%

[nsdeschenes]

I wonder if this is a legacy button setup before scraps 🤔

Wonder if we could use something like a transparent button here?

Tho maybe i'm not fully understanding why we're overriding the opacity like this.

[JoshuaKGoldberg]

Fixed REPLAY-916 for now. I have the ask out in design-eng about copy and will probably do a followup cleanup.