feat: fix duplicate log back behaviour and add tests

app/views/logs/delete_duplicates.html.erb

@@ -1,6 +1,6 @@
 <% content_for :before_content do %>
   <% content_for :title, "Are you sure you want to delete #{@duplicate_logs.count == 1 ? 'this duplicate log' : 'these duplicate logs'}?" %>
-  <%= govuk_back_link href: @log.lettings? ? lettings_log_duplicate_logs_path(@log) : sales_log_duplicate_logs_path(@log) %>
+  <%= govuk_back_link href: @log.lettings? ? lettings_log_duplicate_logs_path(@original_log, original_log_id: @original_log.id) : sales_log_duplicate_logs_path(@original_log, original_log_id: @original_log.id) %>
 <% end %>
 
 <div class="govuk-grid-row">

spec/requests/duplicate_logs_controller_spec.rb

@@ -267,8 +267,8 @@ RSpec.describe DuplicateLogsController, type: :request do
         expect(page).to have_button(text: "Delete this log")
         expect(page).to have_link(text: "Log #{duplicate_log.id}", href: lettings_log_path(duplicate_log.id))
         expect(page).not_to have_link(text: "Log #{id}", href: lettings_log_path(id))
-        expect(page).to have_link(text: "Cancel", href: lettings_log_duplicate_logs_path(id))
-        expect(page).to have_link(text: "Back", href: lettings_log_duplicate_logs_path(id))
+        expect(page).to have_link(text: "Cancel", href: lettings_log_duplicate_logs_path(id, original_log_id: id))
+        expect(page).to have_link(text: "Back", href: lettings_log_duplicate_logs_path(id, original_log_id: id))
       end
     end