Changes to List history for entity watchlist screenings

added the new retro enum value to the entity_watchlist_screenings/items/audit_trail/source response property for the response status 200

the entity_watchlist_screenings/items/client_user_id response property's minLength was decreased from 1 to 0 for the response status 200

the entity_watchlist_screenings/items/search_terms/country response property's minLength was decreased from 2 to 0 for the response status 200

the entity_watchlist_screenings/items/search_terms/document_number response property's minLength was decreased from 4 to 0 for the response status 200

the entity_watchlist_screenings/items/search_terms/legal_name response property's minLength was decreased from 1 to 0 for the response status 200