fix(Checkbox): handle change on root element

[layershifter]

Fixes #3502.

In SUI the whole area of slider is clickable, previously we had an behavior mismatch. This PR fixes it.

Before

After

[codecov-io]

Codecov Report

Merging #3693 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3693      +/-   ##
==========================================
+ Coverage   99.83%   99.83%   +<.01%     
==========================================
  Files         175      175              
  Lines        3116     3120       +4     
==========================================
+ Hits         3111     3115       +4     
  Misses          5        5

Impacted Files	Coverage Δ
src/modules/Checkbox/Checkbox.js	100% <100%> (ø)	⬆️

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[felixmosh]

I'm not sure that the solution is good, I think that what can be fixed using css is better, but it is your decision.
Thanx for the fix!

[layershifter]

I think that what can be fixed using css is better, but it is your decision.

I can agree with it, but we should match SUI behavior 😺