Include purchased storage in banner

Combined storage and free user limit banners should include any
purchased storage as part of the limit

ee/app/components/namespaces/combined_storage_users/base_alert_component.rb

@@ -93,7 +93,7 @@ def free_users_limit
       end
 
       def free_storage_limit
-        limit = root_namespace.actual_limits.storage_size_limit.megabytes
+        limit = ::Namespaces::Storage::RootSize.new(root_namespace).dashboard_limit
         number_to_human_size(limit, precision: 0)
       end
 

ee/spec/components/namespaces/combined_storage_users/non_owner_alert_component_spec.rb

@@ -88,6 +88,15 @@
           expect(page).to have_content(alert_title)
         end
       end
+
+      context 'when the user has purchased additional storage' do
+        it 'includes the purchased storage in the alert' do
+          namespace.additional_purchased_storage_size = 10_240
+          render_inline(component)
+
+          expect(page).to have_content('15 GiB')
+        end
+      end
     end
 
     context 'when not over one of the limits' do

ee/spec/components/namespaces/combined_storage_users/owner_alert_component_spec.rb

@@ -88,6 +88,15 @@
           expect(page).to have_content(alert_title)
         end
       end
+
+      context 'when the user has purchased additional storage' do
+        it 'includes the purchased storage in the alert' do
+          namespace.additional_purchased_storage_size = 10_240
+          render_inline(component)
+
+          expect(page).to have_content('15 GiB')
+        end
+      end
     end
 
     context 'when not over one of the limits' do