Migrate Home page animation to CSS transitions and remove react-transition-group

[mstange]

Main branch | Deploy preview

This removes our usage of react-transition-group. We were only using it for the horizontal slide-in animation that occurs on the home page when we have a WebChannel and detect that the profiler button is in the toolbar.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.38%. Comparing base (9941957) to head (2a7d07e).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5649      +/-   ##
==========================================
- Coverage   85.44%   85.38%   -0.07%     
==========================================
  Files         321      322       +1     
  Lines       32072    32099      +27     
  Branches     8837     8840       +3     
==========================================
+ Hits        27405    27408       +3     
- Misses       4236     4260      +24     
  Partials      431      431              

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