Setting a user picker value via behaviours does not work in JSD portal if the logged in user is a customer

Steps to reproduce:

• Create a single/multi user picker field
• Create a behaviour with an initaliser that sets a user in the field

If you browse to the create request screen via the portal as an admin user, you will see the user picker is correctly populated. If you browse as a customer (no permission to login to standard Jira UI) then this will not work.

Root cause seems to be Behaviours calling the Jira REST API to check if the user exists, customer only users are not permitted to use this REST API and their requests will be redirected back to the portal.

When in a JSD context, the JSD specific REST endpoints for user search should be used as these permit customer access.