Fix modulefiles

[MJGaughran]

We were previously using the built modulefile location, instead of the final location that modules get deployed to.

[codecov]

Codecov Report

Attention: Patch coverage is 37.03704% with 17 lines in your changes missing coverage. Please review.

Project coverage is 43.71%. Comparing base (e76ee1e) to head (3842b3e).

Files with missing lines	Patch %	Lines
src/deploy_tools/deploy.py	16.66%	10 Missing ⚠️
src/deploy_tools/modulefile.py	37.50%	5 Missing ⚠️
src/deploy_tools/layout.py	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #15      +/-   ##
==========================================
+ Coverage   43.50%   43.71%   +0.21%     
==========================================
  Files          23       23              
  Lines         777      780       +3     
==========================================
+ Hits          338      341       +3     
  Misses        439      439              

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