Enable seat usage export

Allow group owners to export seat usage data as CSV file.

https://gitlab.com/gitlab-org/gitlab/-/issues/262877.

Changelog: added
EE: true

doc/subscriptions/gitlab_com/index.md

@@ -120,6 +120,20 @@ For example:
 | Amir       | `ami`         | Yes     |
 | Amir       | `amr`         | No      |
 
+### Export seat usage
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/262877) in GitLab 14.2.
+
+To export seat usage data as a CSV file:
+
+1. On the top bar, select **Menu > Groups** and find your group.
+1. On the left sidebar, select **Settings > Billing**.
+1. Under **Seats currently in use**, select **See usage**.
+1. Select **Export list**.
+
+The generated list contains all seats being used,
+and is not affected by the current search.
+
 ## Subscription expiry
 
 When your subscription expires, you can continue to use paid features of GitLab for 14 days.

ee/app/controllers/groups/seat_usage_controller.rb

@@ -4,7 +4,6 @@ class Groups::SeatUsageController < Groups::ApplicationController
   before_action :verify_top_level_group
   before_action :authorize_admin_group_member!
   before_action :verify_namespace_plan_check_enabled
-  before_action :verify_seat_usage_export_enabled, if: -> { request.format.csv? }
 
   layout "group_settings"
 
@@ -40,8 +39,4 @@ class Groups::SeatUsageController < Groups::ApplicationController
   def verify_top_level_group
     not_found unless group.root?
   end
-
-  def verify_seat_usage_export_enabled
-    not_found unless Feature.enabled?(:seat_usage_export, group, default_enabled: :yaml)
-  end
 end

ee/app/views/groups/seat_usage/show.html.haml

 - page_title s_('SeatUsage|Seat usage')
 - add_to_breadcrumbs _('Billing'), group_billings_path(@group)
 
-#js-seat-usage{ data: { namespace_id: @group.id, namespace_name: @group.name, seat_usage_export_path: (group_seat_usage_path(@group, format: :csv) if Feature.enabled?(:seat_usage_export, @group, default_enabled: :yaml)) } }
+#js-seat-usage{ data: { namespace_id: @group.id, namespace_name: @group.name, seat_usage_export_path: group_seat_usage_path(@group, format: :csv) } }

ee/config/feature_flags/development/seat_usage_export.yml

----
-name: seat_usage_export
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/67202
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/337397
-milestone: '14.2'
-type: development
-group: group::utilization
-default_enabled: false

ee/spec/controllers/groups/seat_usage_controller_spec.rb

@@ -24,10 +24,6 @@ RSpec.describe Groups::SeatUsageController do
       end
 
       context 'when html format' do
-        before do
-          stub_feature_flags(seat_usage_export: false)
-        end
-
         it 'renders show with 200 status code' do
           get_show
 
@@ -54,21 +50,8 @@ RSpec.describe Groups::SeatUsageController do
           expect(response).to have_gitlab_http_status(:not_found)
         end
 
-        context 'when seat_usage_export feature flag is disabled' do
-          before do
-            stub_feature_flags(seat_usage_export: false)
-          end
-
-          it 'responds with 404 status code' do
-            get_show(format: :csv)
-
-            expect(response).to have_gitlab_http_status(:not_found)
-          end
-        end
-
-        context 'when seat_usage_export feature flag is enabled' do
+        context 'when the group is a top-level group' do
           before do
-            stub_feature_flags(seat_usage_export: true)
             expect(Groups::SeatUsageExportService).to receive(:execute).with(group, user).and_return(result)
           end