Show the Trial Status widget in the super sidebar

What does this MR do and why?

Show the Trial Status widget in the super sidebar when group has an active trial.

Screenshots or screen recordings

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How to set up and validate locally

1. Start the GDK in SaaS mode. Typically, this is done by setting the GITLAB_SIMULATE_SAAS environment variable:

   gdk stop
   export GITLAB_SIMULATE_SAAS=1
   gdk start

2. Enable the check_namespace_plan application setting:

   echo "ApplicationSetting.first.update(check_namespace_plan: true)" | rails c

3. Enable the new nav:

   1. Enable the feature flag:

      echo "Feature.enable(:super_sidebar_nav)" | rails c

   2. Enable the user setting from the user dropdown:

      

4. Create a new top-level group.
5. Start a trial for the group you've just created in the rails console:

   group = Group.last
   ultimate_plan = Plan.find_by_name("ultimate_trial")
   trial_start_date = -5.days.from_now
   trial_end_date = trial_start_date + 30.days
   
   gitlab_subscription = group.gitlab_subscription
   gitlab_subscription.hosted_plan_id = ultimate_plan.id
   gitlab_subscription.trial = true
   gitlab_subscription.trial_starts_on = trial_start_date
   gitlab_subscription.trial_ends_on = trial_end_date
   gitlab_subscription.save!
   
   group.web_url # Prints the group's URL for convenience

6. Navigate to the group and notice the trial status widget in the left sidebar.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #406756 (closed)