compile: fix export when artifacts contains a folder

[alessio-perugini]

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What kind of change does this PR introduce?

Fixes the export-dir, when it tries to copy a folder it crashes.

What is the current behavior?

The copy mechanism fails to copy the dir because it's treated as a file, and the compile exits with error code 1

What is the new behavior?

We filter out the directories and copy only exported binaries files.

Does this PR introduce a breaking change, and is titled accordingly?

Other information

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.58%. Comparing base (84fc413) to head (05f1851).
Report is 5 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2788      +/-   ##
==========================================
+ Coverage   67.57%   67.58%   +0.01%     
==========================================
  Files         238      238              
  Lines       22362    22363       +1     
==========================================
+ Hits        15111    15115       +4     
+ Misses       6062     6060       -2     
+ Partials     1189     1188       -1     

Flag	Coverage Δ
unit	67.58% <100.00%> (+0.01%)	⬆️

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