Only show recommended tab for opt-in users (bug 1097332)

`trigger('reload_chrome')` triggers [this](https://github.com/mozilla/fireplace/blob/master/src/media/js/main.js#L165) which will include [this](https://github.com/robhudson/fireplace/blob/1097332-recommended-tab-opt-out/src/media/js/main.js#L206-L215).