Create unit tests to make sure models/views inherit from Committee owned mixins

[exalate-issue-sync]

Add unit tests to check that every model and viewset correctly inherits from the committee owned mixins. We can have an exception list, such as some of the authentication endpoints

QA Notes

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DEV Notes

For models, we can probably use the django {{get_models()}}. Views are a bit tougher but DRF might have something for us - if views are really hard, we can split them out into another ticket

We can add tests on the root level since they apply to the whole app

Design

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See full ticket and images here: FECFILE-1875