Migrated linter fix - (Built on django-migrate and NOT main)

[benjmnxu]

Restore backend checks for ohq deployment.

• Black
• Flake
• No Ruff (idk what this is)
• Backend test cases (which we haven't run in like two years lmao)
• No Codecoverage. Uses an outdated django.yaml (We need to add codecoverage token into our secrets)

[benjmnxu]

Main issue with codecov is just the token I believe. Error message on running codecov:

'Unable to locate build via Github Actions API. Please upload with the Codecov repository upload token to resolve issue.'

If the upload token is shared I'll keep looking into it. If it's ohq specific, I'll need to ask Bach or Dan to add it into our secrets

[judtinzhang]

Makes sense, lmk if you stumble into anything else

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (django-migrate@27f57fc). Click here to learn what that means.

Additional details and impacted files

@@                Coverage Diff                @@
##             django-migrate     #312   +/-   ##
=================================================
  Coverage                  ?   98.93%           
=================================================
  Files                     ?       25           
  Lines                     ?     1316           
  Branches                  ?        0           
=================================================
  Hits                      ?     1302           
  Misses                    ?       14           
  Partials                  ?        0           

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[benjmnxu]

Codecov token added. All tests pass.