Add back removed id

app/models/form/sales/pages/uprn_confirmation.rb

@@ -1,6 +1,7 @@
 class Form::Sales::Pages::UprnConfirmation < ::Form::Page
   def initialize(id, hsh, subsection)
     super
+    @id = "uprn_confirmation"
     @header = "We found an address that might be this property"
     @copy_key = "sales.property.uprn_confirmed"
   end