Complete checkout using `checkoutCompleteWithTokenizedPaymentV3` from private app

[shohei-t]

Hi, I am developing a private app for my client and now working on checkout feature.

I read this document and it says completing checkout via Storefront API is only allowed for sales channel.

https://shopify.dev/custom-storefronts/checkout#complete-the-checkout

But, No errors returned when I called `checkoutCompleteWithTokenizedPaymentV3` from Shopify GraphiQL App.

Does it mean this mutation can be used from private app ?

Or webUrl is the only option ?