Fix failing unit tests

[kelly-sovacool]

Need to change how some results files are compared instead of byte-by-byte. We already have great test coverage in the R package, so having unit tests in this workflow isn't strictly necessary, but would be nice to have in case there are file I/O issues.

pytest status

unit test file	status
test_combine_benchmarks	✅
test_combine_hp_performance	❌
test_combine_results	✅
test_find_feature_importance	✅
test_plot_benchmarks	❌
test_plot_feature_importance	❌
test_plot_hp_performance	✅
test_plot_performance	❌
test_preprocess_data	❌
test_render_report	❌
test_run_ml	❌

[kelly-sovacool]

Consider only addressing #27, because the mikropml R package already includes great unit tests.