Fix focus and navigation for ThumbnailNavigation

[marlo-longley]

Closes #4195

@seanaery does this help? Locally for me this fixed it and looks like it's fixed on the Netlify preview below. I think it was interfering with the handleKeyDown method in the parent ThumbnailNavigation.

I'll have to look at the a11y issues another time. Good catch!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.1%. Comparing base (4e9c9b3) to head (7af6a1b).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #4196     +/-   ##
=======================================
+ Coverage   95.1%   95.1%   +0.1%     
=======================================
  Files        326     326             
  Lines      16192   16199      +7     
  Branches    2545    2549      +4     
=======================================
+ Hits       15391   15398      +7     
  Misses       796     796             
  Partials       5       5             

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[seanaery]

@marlo-longley Yes--that definitely fixes it! 🎉 Just checked out your branch and it is behaving how I'd expect it to. Thank you so much for the quick work on this one!

[seanaery]

@marlo-longley Oh, actually -- spoke too soon (sorry). This change lets me navigate with left/right keys about four times in either direction after clicking a thumb. But after that, it won't go further and instead starts scrolling the thumb pane instead of advancing to the next page. Very strange! So this is progress, but not quite yet the expected behavior.

[marlo-longley]

Ahh OK I guess I didn't try more than 4 clicks?? Let me see...thanks @seanaery

[marlo-longley]

@seanaery give this a try?

[seanaery]

@marlo-longley Yes--excellent! That is working for me. Tested with thumbs in either position (right or bottom), and works correctly even in gallery view. Thanks!