[BUG] unit test failures due to external dataset downloads

[lovettchris]

Describe the bug

We've seen some test failures caused by remote servers being unavailable, like this one: https://github.com/microsoft/archai/actions/runs/4621878743/jobs/8173850396

Perhaps we should figure out how to cache all these remote datasets in an azure blob store and fetch them from there so that unit tests are not dependent on the availability of external datasets.

To Reproduce See https://github.com/microsoft/archai/actions/runs/4621878743/jobs/8173850396

Expected behavior A clear and concise description of what you expected to happen.

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Desktop (please complete the following information):

• OS: [e.g. Ubuntu Linux]
• Virtual Environment [e.g. conda, venv]
• Python Version [e.g. 3.7]

Additional context Add any other context about the problem here.