BarBackground and BarRectangles read activeIndex from context instead of props

[PavelVanecek]

Description

One less prop that was not meant to be a prop

Related Issue

#3717

Motivation and Context

No element cloning

How Has This Been Tested?

npm test

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• I have added a storybook story or extended an existing story to show my changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.17%. Comparing base (1d60cc6) to head (17ed4d7).
Report is 7 commits behind head on 3.x.

Additional details and impacted files

@@            Coverage Diff             @@
##              3.x    #4459      +/-   ##
==========================================
+ Coverage   95.09%   95.17%   +0.08%     
==========================================
  Files         107      111       +4     
  Lines       20871    21303     +432     
  Branches     2851     2933      +82     
==========================================
+ Hits        19848    20276     +428     
- Misses       1017     1021       +4     
  Partials        6        6              

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