Disable stubbed application settings in two new spec files

Signed-off-by: Rémy Coutable <remy@rymai.me>

spec/controllers/admin/application_settings_controller_spec.rb

 require 'spec_helper'
 
 describe Admin::ApplicationSettingsController do
+  include StubENV
+
   let(:group) { create(:group) }
   let(:project) { create(:project, namespace: group) }
   let(:admin) { create(:admin) }
   let(:user) { create(:user)}
 
+  before do
+    stub_env('IN_MEMORY_APPLICATION_SETTINGS', 'false')
+  end
+
   describe 'PUT #update' do
     before do
       sign_in(admin)

spec/features/ci_shared_runner_settings_spec.rb

 require 'spec_helper'
 
 feature 'CI shared runner settings', feature: true do
+  include StubENV
+
   let(:admin) { create(:admin) }
   let(:group) { create(:group, :with_build_minutes) }
   let!(:project) { create(:project, namespace: group, shared_runners_enabled: true) }
 
   before do
+    stub_env('IN_MEMORY_APPLICATION_SETTINGS', 'false')
     login_as(admin)
   end