feat(pricing/ai): improve billing metered pricing + add pricing on ai chat (#14092)

## TODO:

- [x] display "yearly" or "monthly" wording everywhere it's needed
- [ ] Add button with "downgrade" or "upgrade" to save the change of
credits price + modal to validate
- [x] Add renewal date 
- [ ] Implement
https://docs.stripe.com/billing/subscriptions/subscription-schedules for
`switchFromYearlyToMonthly` and decrease number of credits

packages/twenty-server/src/engine/core-modules/billing-webhook/utils/get-deleted-stripe-subscription-item-ids-from-stripe-subscription-event.util.ts

@@ -21,10 +21,9 @@ export const getDeletedStripeSubscriptionItemIdsFromStripeSubscriptionEvent = (
   const subscriptionItemIds =
     event.data.object.items.data.map((item) => item.id) ?? [];
 
-  const deletedSubscriptionItemIds =
+  return (
     event.data.previous_attributes?.items?.data
       .filter((item) => !subscriptionItemIds.includes(item.id))
-      .map((item) => item.id) ?? [];
-
-  return deletedSubscriptionItemIds;
+      .map((item) => item.id) ?? []
+  );
 };