Remove unnecessary backend call from Package#show

We already have the file list requested, we don't need to ask the backend again
about the _service file. This removes ~100ms from the request time.

src/api/app/controllers/webui/package_controller.rb

@@ -86,7 +86,7 @@ def show
 
     @comments = @package.comments.includes(:user)
     @comment = Comment.new
-    @services = Backend::Api::Sources::Package.service(@project.name, @package.name)
+    @services = @files.any? { |file| file[:name] == '_service' }
 
     switch_to_webui2
   end