fix(scroll) clicking on scroll doesn't close autosuggest

[darrenjennings]

• destroy event listeners in beforeDestroy lifecycle
• tests(listener) trigger mousedown as well

Fixes #63

[codecov]

Codecov Report

Merging #64 into master will decrease coverage by 0.55%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##           master      #64      +/-   ##
==========================================
- Coverage   82.73%   82.18%   -0.56%     
==========================================
  Files           1        1              
  Lines         168      174       +6     
  Branches       51       51              
==========================================
+ Hits          139      143       +4     
- Misses          9       11       +2     
  Partials       20       20

Impacted Files	Coverage Δ
src/Autosuggest.vue	82.18% <57.14%> (-0.56%)	⬇️

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