Convert customize homepage from experiment to ff

- success was declared on the experiment, but we should
  allow self managed to absorbe this change for 1 cycle too.

app/controllers/root_controller.rb

@@ -69,7 +69,7 @@ class RootController < Dashboard::ProjectsController
   end
 
   def customize_homepage
-    @customize_homepage = experiment_enabled?(:customize_homepage)
+    @customize_homepage = Feature.enabled?(:customize_homepage, default_enabled: :yaml)
   end
 end
 

changelogs/unreleased/299895-experiment-cleanup-customize_homepage-banner.yml

+---
+title: Enable customize homepage banner by default
+merge_request: 54357
+author:
+type: added

config/feature_flags/experiment/customize_homepage_experiment_percentage.yml → config/feature_flags/development/customize_homepage.yml

 ---
-name: customize_homepage_experiment_percentage
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/39348
-rollout_issue_url: https://gitlab.com/gitlab-org/growth/team-tasks/-/issues/187
-milestone: '13.4'
-type: experiment
+name: customize_homepage
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/54357
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/299895
+milestone: '13.10'
+type: development
 group: group::expansion
-default_enabled: false
+default_enabled: true

lib/gitlab/experimentation.rb

@@ -58,10 +58,6 @@ module Gitlab
         tracking_category: 'Growth::Conversion::Experiment::ContactSalesInApp',
         use_backwards_compatible_subject_index: true
       },
-      customize_homepage: {
-        tracking_category: 'Growth::Expansion::Experiment::CustomizeHomepage',
-        use_backwards_compatible_subject_index: true
-      },
       group_only_trials: {
         tracking_category: 'Growth::Conversion::Experiment::GroupOnlyTrials',
         use_backwards_compatible_subject_index: true

spec/controllers/root_controller_spec.rb

@@ -123,11 +123,7 @@ RSpec.describe RootController do
           expect(response).to render_template 'dashboard/projects/index'
         end
 
-        context 'when experiment is enabled' do
-          before do
-            stub_experiment_for_subject(customize_homepage: true)
-          end
-
+        context 'when customize_homepage is enabled' do
           it 'renders the default dashboard' do
             get :index
 
@@ -135,9 +131,9 @@ RSpec.describe RootController do
           end
         end
 
-        context 'when experiment not enabled' do
+        context 'when customize_homepage is not enabled' do
           before do
-            stub_experiment(customize_homepage: false)
+            stub_feature_flags(customize_homepage: false)
           end
 
           it 'renders the default dashboard' do

spec/lib/gitlab/experimentation_spec.rb

@@ -13,7 +13,6 @@ RSpec.describe Gitlab::Experimentation::EXPERIMENTS do
       :invite_members_version_b,
       :invite_members_empty_group_version_a,
       :contact_sales_btn_in_app,
-      :customize_homepage,
       :group_only_trials
     ]