Refactor integration test "arrange" step for auth objects

[Sherwin-14]

I've added the fixtures but it seems like a lot more errors are pop up.

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📚 Documentation preview 📚: https://earthaccess--752.org.readthedocs.build/en/752/

[mfisher87]

Converted to draft until we can figure out new errors

[mfisher87]

ERROR tests/integration/test_cloud_download.py::test_earthaccess_can_download_cloud_collection_granules[daac0] - assert False is True
 +  where False = <earthaccess.auth.Auth object at 0x7f878cba0310>.authenticated

Looks like our session isn't authenticated as expected. Perhaps we could debug tomorrow during the hack day? I know that's not a very accessible time of day in your timezone, so if you aren't able to make it, I'll plan on spending that time investigating and share back here :)