Fix(Instance VSA): reinstate sidebar templates

When this MR merged:
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/39368

It removed templates that are still in use on the
instance level Value Stream Analytics page.

This MR re-introduces those templates.

MR:
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/39368

Issues:
https://gitlab.com/gitlab-org/gitlab/-/issues/233833
https://gitlab.com/gitlab-org/gitlab/-/issues/205909
https://gitlab.com/gitlab-org/gitlab/-/issues/224716

ee/config/routes/analytics.rb

@@ -4,7 +4,6 @@ namespace :analytics do
   root to: redirect('admin/dev_ops_score')
 
   constraints(-> (req) { Gitlab::Analytics.cycle_analytics_enabled? }) do
-    resource :cycle_analytics, only: :show, path: 'value_stream_analytics'
     scope module: :cycle_analytics, as: 'cycle_analytics', path: 'value_stream_analytics' do
       resources :stages, only: [:index, :create, :update, :destroy] do
         member do

ee/spec/controllers/analytics/cycle_analytics_controller_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Analytics::CycleAnalyticsController do
-  let(:user) { create(:user) }
-
-  before do
-    sign_in(user)
-  end
-
-  describe 'usage counter' do
-    it 'increments usage counter' do
-      expect(Gitlab::UsageDataCounters::CycleAnalyticsCounter).to receive(:count).with(:views)
-
-      get(:show)
-
-      expect(response).to be_successful
-    end
-  end
-
-  describe 'GET show' do
-    it 'renders `show` template' do
-      stub_feature_flags(Gitlab::Analytics::CYCLE_ANALYTICS_FEATURE_FLAG => true)
-
-      get :show
-
-      expect(response).to render_template :show
-    end
-
-    it 'renders `404` when feature flag is disabled' do
-      stub_feature_flags(Gitlab::Analytics::CYCLE_ANALYTICS_FEATURE_FLAG => false)
-
-      get :show
-
-      expect(response).to have_gitlab_http_status(:not_found)
-    end
-  end
-end