Add AI preference options

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Description Adds the "AI preference" option in the user profile so users can express their AI preferences. This is only displayed for users that have sounds. That preference can also be included as a sound serializer field in the API, and as a user serializer field in the API.

Also adds some help text and functions in the sound describe form to add GenAI tag for sounds generated with generative AI.

Deployment steps: Migrate DB. Also, we'll need to update FAQ section with the meaning of the AI preference options, and API docs.