Enable test_aegis_classifier and test_instruction_data_guard_classifier

[sarahyurick]

#421 added PyTests for all of our supported classifiers. However, we are currently skipping the tests for the Aegis and Instruction-Data-Guard classifiers (which require the user to pass a Hugging Face token) until we download and cache the models to our self-hosted GPU runner. This method is preferred over passing a Hugging Face token into the tests because we do not want to get rate limited by Hugging Face.

We should be able to enable these tests after I am able to add the models to .cache/huggingface/hub (wherever the Hugging Face cache directory is stored on our runner).