Check parents when rendering 'pending deletion' badges

If a group is scheduled for deletion, a badge is shown on the group
list page. This change will also show those badges for child items
of the to-be-deleted group.

Changelog: added
EE: true

ee/app/serializers/ee/group_child_entity.rb

@@ -7,7 +7,7 @@ module GroupChildEntity
     prepended do
       # For both group and project
       expose :marked_for_deletion do |instance|
-        instance.marked_for_deletion?
+        instance.self_or_ancestor_marked_for_deletion.present?
       end
       expose :compliance_management_frameworks, if: ->(_instance, _options) { compliance_framework_available? }

ee/spec/serializers/ee/group_child_entity_spec.rb

@@ -2,7 +2,7 @@
 require 'spec_helper'
-RSpec.describe GroupChildEntity do
+RSpec.describe GroupChildEntity, feature_category: :groups_and_projects do
   include ExternalAuthorizationServiceHelpers
   include Gitlab::Routing.url_helpers
@@ -74,4 +74,35 @@
       end
     end
   end
+
+  describe 'marked_for_deletion' do
+    let_it_be(:subgroup) { create(:group, name: 'subgroup', parent: group) }
+    let_it_be(:sub_subgroup) { create(:group, name: 'subsubgroup', parent: subgroup) }
+    let_it_be(:project) { create(:project, name: 'project 1', group: group) }
+
+    before do
+      stub_licensed_features(adjourned_deletion_for_projects_and_groups: true)
+      stub_application_setting(deletion_adjourned_period: 14)
+    end
+
+    context 'when group is marked for deletion' do
+      before_all do
+        create(:group_deletion_schedule, group: group, marked_for_deletion_on: Date.today, deleting_user: user)
+      end
+
+      it 'returns true for child projects and groups' do
+        [group, subgroup, sub_subgroup, project].each do |object|
+          expect(described_class.new(object, request: request).as_json[:marked_for_deletion]).to eq(true)
+        end
+      end
+    end
+
+    context 'when group is not marked for deletion' do
+      it 'returns false for child projects and groups' do
+        [group, subgroup, sub_subgroup, project].each do |object|
+          expect(described_class.new(object, request: request).as_json[:marked_for_deletion]).to eq(false)
+        end
+      end
+    end
+  end
 end