API integration

Description Ticket Severity
When identifying a site, principal_investigator PUT calls should validate the uniqueness of cros_pi_id and sponsors_pi_id fields, and does not return an error if the call specifies a preexisting value for either field. CHK-20128 3
The Study Site API (POST or PUT) allows the creation or update of a site with a duplicate cros_site_id or sponsors_site_id value. CHK-27914 3
When a user updates a submission activity date, the published Activity Change Message includes a null value for "updated_by." CHK-38494 3