CLDC-4019: Update error messaging on referral type question to reflect categories (#3045)
* Add validation for referral type when permanently decanted from PRP-only housing
* Remove unnecessary error adding, PRP and different landlord is possible
* Update tests
internal_transfer:"Answer cannot be internal transfer as it’s the same landlord on the tenancy agreement and the household had either a fixed-term or lifetime local authority general needs tenancy immediately before this letting."
referral_type:
leaving_last_settled_home:
reason_permanently_decanted:"Answer must be from a PRP-only housing register or waiting list (no local authority involvement) as the tenant was permanently decanted from another property owned by this landlord."