Upgrade django_health_checks

[rhysyngsun]

What are the relevant tickets?

N/A

Description (What does it do?)

Upgrade django-health-checks to the latest version. This included breaking changes to the setup so that's addressed here. The migration check did not carry over as they dropped that because the django check framework is supposed to be used to check that.

How can this be tested?

Run the app, you should then be able to access the health check urls:

http://mitxonline.odl.local/health/startup/?format=json
http://mitxonline.odl.local/health/liveness/?format=json
http://mitxonline.odl.local/health/readiness/?format=json
http://mitxonline.odl.local/health/full/?format=json

[github-actions]

OpenAPI Changes

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## Changes for v1.yaml:
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## Changes for v2.yaml:
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Unexpected changes? Ensure your branch is up-to-date with main (consider rebasing).