closes https://github.com/TryGhost/Team/issues/1238
- previously returned 500 errors when a subscription had multiple prices due to external tampering on Stripe directly
- instead now returns 400 Bad Request error when subscriptions don't have right number of prices
no-issue
Since we do not necessarily have a single stripe product anymore, we
should be checking if an invoice webhook is for a stripe product which
we know about. We use the Products repository to search our database for
one.
no-issue
1. We do not want to store payment events for payments of 0 value
2. Stripe webhooks can arrive and be processed "out of order", which can
result in us attempting to add a payment event for a member which
does not yet exist. The change here will 404 in such (edge) cases, so
that Stripe will retry the webhook at a later point, when the Member
has been created, allowing us to store the payment event.
