The relationship editor wrongly preserves a date previously set even when the new type of relationship doesn’t support any date attribute, resulting in an ISE when submitting the form.

Steps to reproduce:

1. Open the form to create a new work
2. Fill a random name
3. Add a “composer” relationship to an artist with a specific year
4. Change the relationship type to “previous attribution”
   At this point, the year is correctly not visible in the Edit Relationship dialog box, but it is still wrongly visible in the Relationships field set.
5. Submit the form and get an ISE; See attached error message hitting Postgres and the full JSON for data query.