[App Bridge]: Missing `shopify.ready` implementation

[Kashuab]

Not sure why I can't find documentation on this. But there's a Promise you can await to make calls when app bridge is ready.

For example:

await shopify.ready;

shopify.modal.show('example-modal')

Helpful for showing things like onboarding modals when the page loads. If you call shopify.modal.show too quickly then it doesn't work.

[ctrlaltdylan]

Since these are mocked session tokens, the shopify.ready could potentially just be a async no-op function.