Currently, a number of dossiers in production are for procedures for
individuals, but don't have a `individual` object.
This is probably because creating the Individual from France Connect
infos fails – but fails quietly, and nullify the relationship.
As a first step, we now raise an exception when the creation from FC
infos fails. We will then identify the issue, and see if we can fix it –
or if we should be resilient to this kind of issues.
