Adds relative inferences for DAU statistic

[danielkberry]

Fulfills https://mozilla-hub.atlassian.net/browse/EXP-4412

[danielkberry]

@mikewilli I'm not sure why the integration test is failing... I didn't touch the requirements file here

[danielkberry]

@mikewilli I'm not sure why the integration test is failing... I didn't touch the requirements file here

It's also not clear to me why only the integration tests are failing and not the unit tests.

[mikewilli]

Code changes look good, I'll see if I can figure out why the tests are failing..

[mikewilli]

So I'm able to reproduce this locally with a new venv by just running python -m pip install -r requirements.txt, both on this branch and on main. I found a discussion and an open bug with pip, and the workaround mentioned there of using --no-deps with pip install fixes the problem for me. I don't see a downside to this for us because we are resolving dependencies with pip-tools generating the requirements.txt, so I think it's a valid workaround for us.

I'll put up a quick PR with this change shortly and then hopefully updating this branch with that change fixes the issue.

Still not sure why this suddenly popped up now. Perhaps some cached dependencies that expired or a particular dep update.