fix: drop "known" from "You must answer UPRN known"

app/services/bulk_upload/lettings/year2023/row_parser.rb

@@ -435,7 +435,7 @@ private
 
   def validate_uprn_exists_if_address_does_not
     if field_18.blank? && field_19.blank? && field_21.blank?
-      errors.add(:field_18, I18n.t("validations.not_answered", question: "UPRN known"))
+      errors.add(:field_18, I18n.t("validations.not_answered", question: "UPRN"))
     end
   end
 

spec/services/bulk_upload/lettings/year2023/row_parser_spec.rb

@@ -830,7 +830,7 @@ RSpec.describe BulkUpload::Lettings::Year2023::RowParser do
         end
 
         it "adds an appropriate error" do
-          expect(parser.errors[:field_18]).to eql(["You must answer UPRN known"])
+          expect(parser.errors[:field_18]).to eql(["You must answer UPRN"])
         end
       end