Sandbox: `payouts.paid` are not correctly handled

[frankie567]

trafficstars

• Sentry: https://polar-sh.sentry.io/issues/5896908775
• Stripe event: evt_1Q8AukDIA9pgt25rq42lX2jF

On Sandbox, Stripe doesn't add the account property on the webhook payload, which prevents us from identifying the Stripe Connect account. Don't know why there is such a difference in behavior. Maybe a configuration issue or a Stripe bug.