fix: don't mask OperationCanceledException triggered by SIGINT

[natemcmaster]

Fixes #459

[codecov]

Codecov Report

Merging #483 (04de66e) into main (6783c5f) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #483   +/-   ##
=======================================
  Coverage   82.19%   82.19%           
=======================================
  Files         106      106           
  Lines        3286     3286           
=======================================
  Hits         2701     2701           
  Misses        585      585           

Impacted Files	Coverage Δ
src/CommandLineUtils/CommandLineApplication.cs	93.58% <ø> (-0.04%)	⬇️
...CommandLineUtils/CommandLineApplication.Execute.cs	70.58% <100.00%> (+1.83%)	⬆️

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