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!