fixed onFileDialogCancel listener overwritting by each instance

[koretskiyav]

What kind of change does this PR introduce?

• bugfix
• feature
• refactoring / style
• build / chore
• documentation

Did you add tests for your changes?

• Yes, my code is well tested
• Not relevant

If relevant, did you update the documentation?

• Yes, I've updated the documentation
• Not relevant

Summary

Fixes #575

Does this PR introduce a breaking change?

Other information

[codecov]

Codecov Report

Merging #611 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #611      +/-   ##
==========================================
- Coverage   99.02%   99.01%   -0.01%     
==========================================
  Files           3        3              
  Lines         205      204       -1     
  Branches       60       59       -1     
==========================================
- Hits          203      202       -1     
  Misses          2        2

Impacted Files	Coverage Δ
src/index.js	99.41% <100%> (-0.01%)	⬇️

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[okonet]

Great work! Thanks for fixing it!

[okonet]

@koretskiyav could you please take a look if #557 is related to this? Also, would be great if you could fill out the summary for the PR.

Thanks!

[koretskiyav]

@okonet I can not reproduce this problem myself, both before this fix and after