Module: Fix enrichment of type info via Module imports

[mlange05]

This addresses issue #428 . Many thanks to @wertysas for the excellent reproducer and test

The problem was essentially that we would drop type info for subroutines if the info enrichment came though type imports on the parent Module. This is easily fixed by including parent imports in the enrichment loop over Imports.

I took the opportunity to also clean up the import on test_module.py in the process.

[github-actions]

Documentation for this branch can be viewed at https://sites.ecmwf.int/docs/loki/448/index.html

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.20%. Comparing base (bcef931) to head (83222f4).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #448   +/-   ##
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  Coverage   93.19%   93.20%           
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  Files         219      219           
  Lines       40908    40929   +21     
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+ Hits        38126    38147   +21     
  Misses       2782     2782           

Flag	Coverage Δ
lint_rules	96.39% <ø> (ø)
loki	93.15% <100.00%> (+<0.01%)	⬆️

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[reuterbal]

Fantastic, many thanks for the excellently described issue @wertysas and neat fix @mlange05!