Checkout/Cart: Consolidate all interactions in components with context

[nerrad]

Note: This is a stretch goal and not intended for the initial release of the blocks.

Right now we use hooks directly in the various components, but it'd be good to have everything flow through the contexts (Checkout/CartProvider, PaymentMethodPaymentProvider, ShippingMethodDataProvider). This could mean using the relevant context hooks directly, or new hooks that expose just a slice of context (for descriptive application).

Rationale:

• Logic related to data, status, state etc is maintained in the the context.
• Contexts can still use the data stores (and relevant hooks), but we can keep those interfaces private and selectively control the public interface (via the context) for extensibility.
• Status management is more centralized and thus easier to maintain.
• Components are more decoupled because if they are not used within a context provider, they will use the default (shimmed and nooped) state exposed on the context hooks. This allows for potential use of some components outside of cart/checkout.
• There is clearer flow for checkout/cart data within the contexts.
• While not verified, I think contexts will potentially work better with React.Suspense api (for potential future iterations).

[github-actions]

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[github-actions]

This issue has been marked as stale because it has not seen any activity within the past 60 days. Our team uses this tool to help surface issues for review. If you are the author of the issue there's no need to comment as it will be looked at.

Internal: After 10 days with no activity this issue will be automatically be closed.

[nerrad]

I'm going to close this issue. Some of this is done, and some of this is accomplished through various refactors as we tighten up how data flows through the app for various needs we work on. So as a separate issue for work to do, I don't think there is much value at this point.