Quarantine a 'Group SAML SSO Enforced SSO' test

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

qa/qa/specs/features/ee/browser_ui/1_manage/group/group_saml_sso_spec.rb

@@ -75,7 +75,7 @@ module QA
         end
       end
 
-      context 'Enforced SSO' do
+      context 'Enforced SSO', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/39607' do
         let(:developer_user) { Resource::User.fabricate_via_api! }
         let(:owner_user) { Resource::User.fabricate_via_api! }