Update uprn question

app/models/form/lettings/questions/uprn.rb

@@ -15,7 +15,7 @@ class Form::Lettings::Questions::Uprn < ::Form::Question
   end
 
   def unanswered_error_message
-    I18n.t("validations.property.uprn.invalid")
+    I18n.t("validations.lettings.property.uprn.invalid")
   end
 
   def get_extra_check_answer_value(log)

spec/models/form/lettings/questions/uprn_spec.rb

@@ -28,7 +28,7 @@ RSpec.describe Form::Lettings::Questions::Uprn, type: :model do
   end
 
   it "has the correct unanswered_error_message" do
-    expect(question.unanswered_error_message).to eq("UPRN must be 12 digits or less.")
+    expect(question.unanswered_error_message).to eq(I18n.t("validations.lettings.property.uprn.invalid"))
   end
 
   describe "get_extra_check_answer_value" do