[bugfix] Slider: should not emit change event when value not changed

[chenjiahan]

No description provided.

[codecov-io]

Codecov Report

Merging #4087 into dev will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              dev    #4087      +/-   ##
==========================================
+ Coverage   94.34%   94.34%   +<.01%     
==========================================
  Files         134      134              
  Lines        2864     2866       +2     
  Branches      260      260              
==========================================
+ Hits         2702     2704       +2     
  Misses        129      129              
  Partials       33       33

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

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