showManageSubscriptions never uses native AppStore method

I noticed that even on a device running iOS15, Purchases.showManageSubscriptions() loads the subscriptions UI via Safari rather than a native action sheet. This seems to be because we have:

  SystemInfo.appleSubscriptionsURL = URL(string: "https://rev.cat/manage-apple-subscription")

This url never passes the isAppleSubscription() test, therefore we always fallback to the openURL() method.

Is this by design?