refactor: apply fixes for flake8 comprehensions (C4)

[mwtoews]

This PR applies the automated "unsafe fix" suggestions from ruff check C4 for comprehensions. All of the changes look like good simplifications.

[codecov]

Codecov Report

Attention: Patch coverage is 89.79592% with 5 lines in your changes missing coverage. Please review.

Project coverage is 75.9%. Comparing base (bb9824e) to head (e9521b5).
Report is 8 commits behind head on develop.

Files with missing lines	Patch %	Lines
flopy/export/netcdf.py	0.0%	1 Missing ⚠️
flopy/export/utils.py	50.0%	1 Missing ⚠️
flopy/plot/crosssection.py	50.0%	1 Missing ⚠️
flopy/plot/plotutil.py	50.0%	1 Missing ⚠️
flopy/utils/zonbud.py	90.0%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #2376     +/-   ##
=========================================
+ Coverage     68.4%   75.9%   +7.5%     
=========================================
  Files          294     294             
  Lines        59390   61638   +2248     
=========================================
+ Hits         40652   46841   +6189     
+ Misses       18738   14797   -3941     

Files with missing lines	Coverage Δ
flopy/discretization/grid.py	76.5% <100.0%> (+0.6%)	⬆️
flopy/export/vtk.py	78.0% <100.0%> (+9.4%)	⬆️
flopy/modflow/mfag.py	91.1% <100.0%> (+0.1%)	⬆️
flopy/modflow/mfpval.py	85.9% <100.0%> (+0.2%)	⬆️
flopy/modflow/mfsfr2.py	87.4% <100.0%> (+0.6%)	⬆️
flopy/modflow/mfuzf1.py	92.0% <100.0%> (+0.5%)	⬆️
flopy/modflow/mfwel.py	90.0% <100.0%> (+2.5%)	⬆️
flopy/utils/cvfdutil.py	82.5% <100.0%> (ø)
flopy/utils/geometry.py	75.1% <ø> (+0.2%)	⬆️
flopy/utils/get_modflow.py	63.9% <100.0%> (+37.6%)	⬆️
... and 10 more

... and 210 files with indirect coverage changes

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