Convert manifest controller spec to request spec (#31596)

spec/controllers/manifests_controller_spec.rb

@@ -1,19 +0,0 @@
-# frozen_string_literal: true
-
-require 'rails_helper'
-
-describe ManifestsController do
-  render_views
-
-  describe 'GET #show' do
-    before do
-      get :show
-    end
-
-    it 'returns http success' do
-      expect(response).to have_http_status(200)
-    end
-
-    it_behaves_like 'cacheable response'
-  end
-end