Support mock.shop as a storeDomain

[frandiox]

Builds on top of #985 , and is related to the new onboarding in #913

Tiny change to support mock.shop as a storeDomain. Any call to storefront.query(...) will hit the mock.shop instead of the storefront API.

Note that mock.shop doesn't work for every query. For example, it throws permission errors when trying to read customer information.

🎩 To test it, add PUBLIC_STORE_DOMAIN="mock.shop" to the .env file in demo-store template, and comment out the customer { ... } selection part of the CartFragment in root.tsx (not supported in mock.shop).

[benjaminsehl]

@teddyhwang @darius-gai — the permission errors for customers, any thoughts on that? intentional? want to keep it?

[teddyhwang]

@teddyhwang @darius-gai — the permission errors for customers, any thoughts on that? intentional? want to keep it?

I don't recall but we might have just forgotten that scope. The only scope we were intentional about not adding was checkout mutations. feel free to add the scope and generate a new token!