I have an app where I basically want to say, when the user cancels their subscription from the stripe page, then redirect them back to the login page / register page on my app! I cannot find a solution for this for the life of me. I cannot seem to find a place to do it in the Stripe Dashboard, and I am using the firebase connection with stripe, so it is all stored in there, but even in there, there is no row that shows a cancellation redirect url... my code is here:

 export async function goToBilliingPortal(){
  const functionRef = app
  .functions('us-central1')
  .httpsCallable('ext-firestore-stripe-subscriptions-createPortalLink');
  const {data} = await functionRef({returnUrl : window.location.origin});
  window.location.assign(data.url);
};

I'm wondering if I can add a field that says like cancel_url in here?