Remove jira_spec from quarantine

spec/features/issuables/markdown_references/jira_spec.rb

 require "rails_helper"
 
-describe "Jira", :js, :quarantine do
+describe "Jira", :js do
   let(:user) { create(:user) }
   let(:actual_project) { create(:project, :public, :repository) }
   let(:merge_request) { create(:merge_request, target_project: actual_project, source_project: actual_project) }