Previously, our Stripe webhook event handler code retrieved the
user's email from Stripe using the stripe.Customer.email attribute.
This led to situations such that whenever the email that Stripe had
did not correspond to a UserProfile in Zulip, the payment flow
failed since we couldn't find a UserProfile associated with the
given email.
Now, we pass in the UserProfile.id in the metadata to Stripe's
checkout Session object, so that we can fetch the correct email
in future Stripe requests.
Eeshan Garg
Vishnu KS