Task/script create contacts for existing users/2768

[andrea-williams]

Card: #2768

How to Test/Run:

1. Follow the steps listed in bc_obps/common/management/commands/check_migrations_with_prod_data.py (regarding making changes to your local bc_obps/.env file.
2. You'll also likely want to comment out lines 73-74 and 80-81 in check_migrations_with_prod_data, so that you can retain a copy of the prod data locally while you test.
3. Sign in to Openshift with the CLI tool
4. Run poetry run python manage.py check_migrations_with_prod_data --pod <pod_name>, where pod_name is the name of a postgres pod in our Openshift PROD env
5. Once you've successfully pulled the prod data into your local "obps" database, run poetry run python manage.py migrate registration 0077 and poetry run python manage.py migrate reporting to apply all Django migrations except for the migration included in this PR
6. Now run poetry run python manage.py migrate registration, which will run the migration included in this PR (registration/0078).

For testing purposes, the migration in this PR contains assertions and print statements for testing purposes and to demonstrate that the migration is working as expected. These assertions and print statements will be deleted from the migration before merging (it's also why the pre-commit hook is failing).

REMEMBER TO DELETE YOUR LOCAL COPY OF THE PROD DATA ONCE YOU'VE FINISHED TESTING!