Why this change?
In the `invites_controller_spec.rb` file, we had several tests that were
checking for assets path in the response's body to determine which
layout has been rendered. However, those test fails if `bin/ember-cli
--build` has been run locally.
What does this change do?
Instead of checking for asset paths to determine the layout that has
been rendered, this change relies on the fact that the `no_ember` layout
has a `no-ember` class on the `body` element. This is more deterministic
as compared to relying on the different asset paths that are rendered in
the response.