Important

Allow past subscribers to view their invoices by updating UI components and backend logic to handle users with a Stripe customer ID but no active subscription.

• Behavior:
  • BillingInvoiceTable and BillingDiscountView now render for past subscribers by checking stripe.customerId instead of activeSubscriptionId.
  • BillingInvoiceTable in BillingSettings.tsx shows invoices for users with a stripe.customerId, even if the subscription is canceled.
• Backend:
  • retrieveInvoiceList in stripeBillingService.ts no longer requires subscriptionId, allowing invoice retrieval for past subscriptions.
  • getInvoices in stripeBillingService.ts fetches invoices for customers without active subscriptions.
• Misc:
  • Removed unused imports and variables in BillingDiscountView.tsx and BillingUsageChart.tsx.

^{This description was created by for 39e6f6a. You can customize this summary. It will automatically update as commits are pushed.}