Enable the instance-level overrides feature

Removes the `instance_level_integration_overrides` feature flag to
enable the instance-level overrides feature.

https://gitlab.com/gitlab-org/gitlab/-/issues/218252
https://gitlab.com/gitlab-org/gitlab/-/issues/336750

Changelog: added

app/controllers/admin/integrations_controller.rb

@@ -8,8 +8,6 @@ class Admin::IntegrationsController < Admin::ApplicationController
   feature_category :integrations
 
   def overrides
-    return render_404 unless instance_level_integration_overrides?
-
     respond_to do |format|
       format.json do
         projects = Project.with_active_integration(integration.class).merge(::Integration.with_custom_settings)

app/helpers/integrations_helper.rb

@@ -129,15 +129,11 @@ module IntegrationsHelper
     [
       { key: 'edit', text: _('Settings'), href: scoped_edit_integration_path(integration) },
       (
-        { key: 'overrides', text: s_('Integrations|Projects using custom settings'), href: scoped_overrides_integration_path(integration) } if integration.instance_level? && instance_level_integration_overrides?
+        { key: 'overrides', text: s_('Integrations|Projects using custom settings'), href: scoped_overrides_integration_path(integration) } if integration.instance_level?
       )
     ].compact
   end
 
-  def instance_level_integration_overrides?
-    Feature.enabled?(:instance_level_integration_overrides, default_enabled: :yaml)
-  end
-
   def jira_issue_breadcrumb_link(issue_reference)
     link_to '', { class: 'gl-display-flex gl-align-items-center gl-white-space-nowrap' } do
       icon = image_tag image_path('illustrations/logos/jira.svg'), width: 15, height: 15, class: 'gl-mr-2'

config/feature_flags/development/instance_level_integration_overrides.yml

----
-name: instance_level_integration_overrides
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/66723
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/336750
-milestone: '14.2'
-type: development
-group: group::integrations
-default_enabled: false

doc/user/admin_area/settings/project_integration_management.md

@@ -61,6 +61,18 @@ integration on all non-configured groups and projects by default.
 
 Resetting an instance-level default setting removes the integration from all projects that have the integration set to use default settings.
 
+### View projects that override the default settings
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/218252) in GitLab 14.2.
+
+You can view which projects in your instance use custom settings that [override the instance-level default settings](#use-custom-settings-for-a-group-or-project-integration)
+for an integration.
+
+1. On the top bar, select **Menu >** **{admin}** **Admin**.
+1. In the left sidebar, select **Settings > Integrations**.
+1. Select an integration.
+1. Select the **Projects using custom settings** tab.
+
 ## Manage group-level default settings for a project integration
 
 > [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/2543) in GitLab 13.6.

spec/controllers/admin/integrations_controller_spec.rb

@@ -131,18 +131,6 @@ RSpec.describe Admin::IntegrationsController do
         expect(response).to render_template 'shared/integrations/overrides'
         expect(assigns(:integration)).to eq(instance_integration)
       end
-
-      context 'when `instance_level_integration_overrides` is not enabled' do
-        before do
-          stub_feature_flags(instance_level_integration_overrides: false)
-        end
-
-        it 'renders a 404' do
-          subject
-
-          expect(response).to have_gitlab_http_status(:not_found)
-        end
-      end
     end
   end
 end

spec/features/admin/integrations/user_activates_mattermost_slash_command_spec.rb

@@ -19,16 +19,4 @@ RSpec.describe 'User activates the instance-level Mattermost Slash Command integ
     expect(page).to have_link('Settings', href: edit_path)
     expect(page).to have_link('Projects using custom settings', href: overrides_path)
   end
-
-  context 'when instance_level_integration_overrides is disabled' do
-    before do
-      stub_feature_flags(instance_level_integration_overrides: false)
-      visit_instance_integration('Mattermost slash commands')
-    end
-
-    it 'does not display the overrides tab' do
-      expect(page).not_to have_link('Settings', href: edit_path)
-      expect(page).not_to have_link('Projects using custom settings', href: overrides_path)
-    end
-  end
 end