De-quarantine CI env var spec

qa/qa/specs/features/browser_ui/4_verify/ci_variable/add_ci_variable_spec.rb

@@ -1,8 +1,7 @@
 # frozen_string_literal: true
 
 module QA
-  # Failure issue: https://gitlab.com/gitlab-org/quality/staging/issues/43
-  context 'Verify', :quarantine do
+  context 'Verify' do
     describe 'CI variable support' do
       it 'user adds a CI variable' do
         Runtime::Browser.visit(:gitlab, Page::Main::Login)