feat: allow split/select to be used in conditions

[iph]

Turns out you can use split (and probably join) in conditions. This adds the functionality for split to be used, which unblocks a few templates found that require that.

[codecov]

Codecov Report

Merging #150 (049a33a) into main (1e58e80) will increase coverage by 0.2%.
The diff coverage is 90.0%.

Additional details and impacted files

Components	Coverage Δ
Parser	75.2% <68.8%> (-0.2%)	⬇️
Intermediate Representation	81.7% <100.0%> (+0.3%)	⬆️
Synthesizers	87.5% <100.0%> (+0.2%)	⬆️
Other	49.7% <ø> (ø)

@@           Coverage Diff           @@
##            main    #150     +/-   ##
=======================================
+ Coverage   81.4%   81.5%   +0.2%     
=======================================
  Files         24      24             
  Lines       2693    2743     +50     
  Branches    2693    2743     +50     
=======================================
+ Hits        2191    2236     +45     
  Misses       342     342             
- Partials     160     165      +5     

Impacted Files	Coverage Δ
src/parser/condition/mod.rs	76.4% <68.8%> (-0.7%)	⬇️
src/ir/conditions/mod.rs	69.2% <100.0%> (+3.1%)	⬆️
src/synthesizer/golang/mod.rs	84.6% <100.0%> (+0.3%)	⬆️
src/synthesizer/typescript/mod.rs	90.6% <100.0%> (+0.2%)	⬆️

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