Unquarantine Add Deploy Key test

qa/qa/specs/features/browser_ui/6_release/deploy_key/add_deploy_key_spec.rb

 # frozen_string_literal: true
 module QA
-  # Failure issue: https://gitlab.com/gitlab-org/quality/staging/issues/26
-  context 'Release', :quarantine do
+  context 'Release' do
     describe 'Deploy key creation' do
       it 'user adds a deploy key' do
         Runtime::Browser.visit(:gitlab, Page::Main::Login)