fix(Dropdown): override onChange in DropdownSearchInput

[layershifter]

Fixes #3122.

[codecov-io]

Codecov Report

Merging #3123 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3123      +/-   ##
==========================================
+ Coverage   99.92%   99.92%   +<.01%     
==========================================
  Files         163      163              
  Lines        2739     2742       +3     
==========================================
+ Hits         2737     2740       +3     
  Misses          2        2

Impacted Files	Coverage Δ
src/modules/Dropdown/Dropdown.js	99.75% <100%> (ø)	⬆️

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[levithomason]

Released in [email protected].