Fix spacing for notices in consultations

When we replaced this with the notice component in the gem, we removed the bottom margin in all cases.
This meant that sometimes, the heading of a section could appear directly underneath a notice with no spacing.

This fix introduces spacing in those cases, but adds a bottom margin when the notice is immediately followed by a banner item (as per the original design)

app/presenters/consultation_presenter.rb

@@ -110,6 +110,10 @@ def attachment_url
     ways_to_respond["attachment_url"]
   end
 
+  def add_margin?
+    final_outcome? || public_feedback_detail || public_feedback_documents?
+  end
+
 private
 
   def display_date_and_time(date, rollback_midnight = false)

app/views/content_items/consultation.html.erb

@@ -31,7 +31,11 @@
       <% content_item_final_outcome = capture do %>
         Visit this page again soon to download the outcome to this public&nbsp;feedback.
       <% end %>
-      <%= render 'govuk_publishing_components/components/notice', title: 'We are analysing your feedback', description_text: content_item_final_outcome, margin_bottom: 0 %>
+      <%= render 'govuk_publishing_components/components/notice',
+        title: 'We are analysing your feedback',
+        description_text: content_item_final_outcome,
+        margin_bottom:(0 unless @content_item.add_margin?)
+      %>
 
     <% elsif @content_item.final_outcome? %>
       <%= render 'govuk_publishing_components/components/notice', title: 'This consultation has concluded' %>