Add usage billing paid tier trial card

What does this MR do and why?

This adds a FE for GitLab credits dashboard paid tier trial mode

References

• https://gitlab.com/gitlab-org/fulfillment/gitlab/-/work_items/3+

Screenshots or screen recordings

See comments

How to set up and validate locally

Either use storybook:

1. yarn storybook:start
2. Open relevant story: http://localhost:6006/?path=/story/ee-usage-quotas-usage-billing-app--paid-tier-trial

Or stub the API with a patch:

diff --git a/ee/lib/gitlab_subscriptions/subscription_usage.rb b/ee/lib/gitlab_subscriptions/subscription_usage.rb
index c05b43097e82..2372887798f1 100644
--- a/ee/lib/gitlab_subscriptions/subscription_usage.rb
+++ b/ee/lib/gitlab_subscriptions/subscription_usage.rb
@@ -137,7 +137,7 @@ def subscription_portal_usage_dashboard_url
 
     def paid_tier_trial
       PaidTierTrial.new(
-        is_active: !!usage_metadata.dig(:paidTierTrial, :isActive),
+        is_active: true, # !!usage_metadata.dig(:paidTierTrial, :isActive),
         declarative_policy_subject: self
       )
     end

Or follow Ammar's instructions in https://gitlab.com/gitlab-org/customers-gitlab-com/-/merge_requests/14412#test-steps to add a real trial wallet.

MR acceptance checklist

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