The PJSIP migration inserts an invalid field in the DB

Given a working trunk configuration with a registration
When I upgrade to wazo 20.13 or later
Then the registration section has the outbound_auth option

Relations are not stored in the DB with the new API. The result is that doing a GET on a migrated trunk will return an 'outbound_auth' field in the registration_section_option section. Then trying to PUT the same body results in an error because the outbound_auth cannot be explicit.