Add missing button to sales address page

app/models/form/sales/questions/postcode_for_full_address.rb

@@ -20,6 +20,7 @@ class Form::Sales::Questions::PostcodeForFullAddress < ::Form::Question
     @disable_clearing_if_not_routed_or_dynamic_answer_options = true
     @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
     @hide_question_number_on_page = true
+    @bottom_guidance_partial = "address_fallback"
   end
 
   QUESTION_NUMBER_FROM_YEAR = { 2023 => 15, 2024 => 16, 2025 => 14 }.freeze