Experience Event and Profile mixins missing '$ref' in defining consent preferences

## What are the schemas that are affected by the issue
https://github.com/RussStringham/xdm/blob/master/schemas/context/experienceevent-privacy.schema.json
https://github.com/RussStringham/xdm/blob/4f45ff8d0b185c27394059c72cd109a6050ee725/schemas/context/profile-privacy.schema.json

XDM build may get impacted due to this.
"npm test" would work but newly added fields will not be usable.

Start by comparing schemas/context/experienceevent-privacy.schema.json and schemas/context/profile-privacy.schema.json, focusing on the consent-preference definitions and their missing "$ref" entries. Run npm test to verify the schema build, and confirm that newly added fields using these mixins are usable.

Written by the indexing model from the issue text.