Remove useless memoization

Everywhere the `details` method is being called is not re-computing the
response, therefore the memoization is pointless.

Removing it here, to avoid the unnecessary compute needed to check
whether the instance variable has already been set.

app/presenters/details_presenter.rb

@@ -11,13 +11,10 @@ def initialize(content_item_details, change_history_presenter, content_embed_pre
     end
 
     def details
-      @details ||=
-        begin
-          updated = content_embed(content_item_details).presence || content_item_details
-          updated = recursively_transform_govspeak(updated)
-          updated[:change_history] = change_history if change_history.present?
-          updated
-        end
+      updated = content_embed(content_item_details).presence || content_item_details
+      updated = recursively_transform_govspeak(updated)
+      updated[:change_history] = change_history if change_history.present?
+      updated
     end
 
   private