TEST: Fix tests for Python 3.12, numpy 2.0, and pytest-xdist

[effigies]

This a quick hack to get tests working.

We should purge pkg_resources and use importlib.resources, but I don't have the energy for that right now.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.79%. Comparing base (66001b1) to head (4d2f4c7).
Report is 91 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #210   +/-   ##
=======================================
  Coverage   95.79%   95.79%           
=======================================
  Files          14       14           
  Lines        1307     1307           
  Branches      259      259           
=======================================
  Hits         1252     1252           
  Misses         52       52           
  Partials        3        3           

Flag	Coverage Δ
unittests	95.79% <100.00%> (ø)

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