New learner created with actual first name from API

When a new learner is created, it currently attempts to parse out the ministry from the user full_name, and for some unknown reason we are then assigning the person's first name from that parsing attempt. Instead we should simply using the first_name (and last_name) attribute from the API call when assigning the names.

With this update, we are also updating the template to show a "Welcome first_name" message on the curator dashboard headers. This info should be integrated into the sidebar as well, but we should attempt to clean up the existing first_name data in the database before doing this as quite a few users have "Allan PSA:EX" as their first name because the ministry parsing fails...