Mock viz subscriptions

app/controllers/carto/api/visualization_presenter.rb

@@ -128,6 +128,7 @@ module Carto
         poro[:related_tables] = related_tables if related
         poro[:synchronization] = synchronization if show_synchronization
         poro[:uses_builder_features] = @visualization.uses_builder_features? if show_uses_builder_features
+        poro[:subscription] = 'do-v2' if @visualization.name == 'my_do_subscription'
 
         poro
       end

app/controllers/carto/api/visualizations_controller.rb

@@ -499,7 +499,8 @@ module Carto
                                                  .with_user_id_not(current_user.id)
                                                  .with_locked(false)
                                                  .with_prefetch_table
-                                                 .build.size
+                                                 .build.size,
+          total_subscriptions: 1
         }
       end
     end