Add import sanity test

[samdoran]

Add a basic sanity test to ensure all Python files are importable.

Note

The sanity test was added to the existing job for simplicity. It should eventually be refactored into a separate test that can run in parallel with the unit tests.

[codecov[bot]]

Codecov Report

Merging #423 (8761f39) into main (598029e) will increase coverage by 0.0%. The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #423   +/-   ##
=====================================
  Coverage   93.6%   93.6%           
=====================================
  Files         59      59           
  Lines       4401    4401           
  Branches     616     616           
=====================================
+ Hits        4120    4121    +1     
+ Misses       153     152    -1     
  Partials     128     128