Adding up & down key navigation (accessibility) feature for Tree component

[priyankar205]

1. Added up & down key navigation in Tree component.

[codecov]

Codecov Report

Merging #1219 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1219      +/-   ##
==========================================
+ Coverage   82.55%   82.56%   +<.01%     
==========================================
  Files         751      752       +1     
  Lines        8854     8859       +5     
  Branches     1246     1178      -68     
==========================================
+ Hits         7309     7314       +5     
  Misses       1530     1530              
  Partials       15       15

Impacted Files	Coverage Δ
packages/react/src/components/Tree/TreeItem.tsx	60.6% <ø> (ø)	⬆️
packages/react/src/lib/accessibility/index.ts	100% <100%> (ø)	⬆️
packages/react/src/components/Tree/Tree.tsx	75.55% <100%> (ø)	⬆️
...c/lib/accessibility/Behaviors/Tree/treeBehavior.ts	100% <100%> (ø)

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