Support empty strings in enums

[ramnes]

Closes #357.

[codecov]

Codecov Report

Merging #358 (c92cb71) into main (72cb706) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main      #358   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           47        47           
  Lines         1420      1420           
=========================================
  Hits          1420      1420           

Impacted Files	Coverage Δ
...i_python_client/parser/properties/enum_property.py	100.00% <100.00%> (ø)

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[dbanty]

Oh awesome, you also fixed it. Thanks so much!