Date format does not include timezone, nor changes if site timezone modified

[brianhogg]

Reproduction Steps

1. Call /wp-json/llms/v1/students/<id>/enrollments for a student ID that has one or more enrollments
2. Modify the timezone of the site
3. Call the endpoint again

Expected Behavior

Date/time changes based on the timezone

Actual Behavior

date_created date_updated stay the same. It seems to be GMT regardless.

Tech Notes

We likely want this in the full ISO format with UTC offset. This likely means a /v2 of the API, or else maybe adding a timezone param?