Update the trial status popover title

What does this MR do and why?

Updates the trial status popover title to better reflect when a user is in a trial and how many days are remaining

Screenshots or screen recordings

How to set up and validate locally

# Turn on billing features in the app through the console (gdk rails c)
ApplicationSetting.first.update(check_namespace_plan: true)
# Create a new User
user = FactoryBot.create(:user, username: 'user_288015', email: 'user.288015@example.org', password: '12345678')
# Create a new Group & assign the new user as its owner
group = FactoryBot.create(:group)
group.add_owner(user)
# Find or create the Ultimate plan
plan = Plan.create_with(title: 'Ultimate (Formerly Gold)').find_or_create_by(name: :ultimate)
# Create a new subscription for the Group
GitlabSubscription.create(namespace: group, hosted_plan: plan, seats: 10, start_date: Date.current, end_date: Date.current.advance(years: 1), trial: true, trial_starts_on: Date.current, trial_ends_on: Date.current.advance(days: 30))

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 #324887 (closed)