Apply changes recomended by merge request coach

app/models/group.rb

@@ -416,6 +416,10 @@ class Group < Namespace
     super || ::Gitlab::CurrentSettings.default_project_creation
   end
+  def subgroup_creation_level
+    super || ::Gitlab::Access::MAINTAINER_SUBGROUP_ACCESS
+  end
+
   private
   def update_two_factor_requirement

spec/controllers/admin/groups_controller_spec.rb

@@ -70,8 +70,6 @@ describe Admin::GroupsController do
     end
     it 'updates the subgroup_creation_level successfully' do
-      OWNER = ::Gitlab::Access::OWNER_SUBGROUP_ACCESS
-
       expect do
         post :update,
              params: { id: group.to_param,

spec/services/groups/create_service_spec.rb

-# coding: utf-8
 # frozen_string_literal: true
 require 'spec_helper'
@@ -88,14 +87,6 @@ describe Groups::CreateService, '#execute' do
         it { is_expected.to be_persisted }
       end
-
-      context 'as maintainer' do
-        before do
-          group.add_maintainer(user)
-        end
-
-        it { is_expected.to be_persisted }
-      end
     end
   end