Add an unset option to the collapse active key

[Ahmed-Sarkawt]

Having an unset option to provide easier customization to the collapse

[vercel]

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🔍 Inspect: https://vercel.com/react-component/collapse/6qe4in9iw
✅ Preview: https://collapse-git-patch-1.react-component.vercel.app

[codecov]

Codecov Report

Merging #180 (94b6195) into master (ea1ab91) will decrease coverage by 0.91%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #180      +/-   ##
==========================================
- Coverage   99.04%   98.13%   -0.92%     
==========================================
  Files           4        4              
  Lines         105      107       +2     
  Branches       33       34       +1     
==========================================
+ Hits          104      105       +1     
- Misses          1        2       +1     

Impacted Files	Coverage Δ
src/Collapse.tsx	98.43% <66.66%> (-1.57%)	⬇️

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[Ahmed-Sarkawt]

Having an unset option to the activeKey prop in order to make the component easier to handle

[lgtm-com]

This pull request introduces 12 alerts when merging 06c92a3 into ea1ab91 - view on LGTM.com

new alerts:

• 12 for Syntax error

[Ahmed-Sarkawt]

Update the condition of the if statement in Collapse component