Merge branch 'qa/de-quarantine-api-test-from-plan' into 'master'

De-quarantine API test suite from the Plan DevOps stage

Closes gitlab-org/quality/staging#48

See merge request gitlab-org/gitlab-ee!14546

qa/qa/specs/features/api/2_plan/ee_epics_milestone_dates_spec.rb

 # frozen_string_literal: true
 
 module QA
-  # Failure issue: https://gitlab.com/gitlab-org/quality/staging/issues/48
-  context 'Plan', :quarantine do
+  context 'Plan' do
     describe 'Epics milestone dates API' do
       before(:context) do
         @api_client = Runtime::API::Client.new(:gitlab)