feat(dropdown): Make show/hide events cancelable + Add toggle event

[jacobmllr95]

No description provided.

[codecov]

Codecov Report

Merging #1807 into dev will decrease coverage by 0.27%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##              dev    #1807      +/-   ##
==========================================
- Coverage   61.04%   60.76%   -0.28%     
==========================================
  Files         154      154              
  Lines        2862     2875      +13     
  Branches      791      795       +4     
==========================================
  Hits         1747     1747              
- Misses        800      809       +9     
- Partials      315      319       +4

Impacted Files	Coverage Δ
src/mixins/dropdown.js	7.14% <0%> (-0.74%)	⬇️

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[pi0]

Thanks :)