Move payment method state to PaymentMethodProvider

[sirbrillig]

Proposed Changes

CheckoutProvider does too much. Previous efforts have been made (#81796, #81793, #80529) to move toward making it just a wrapper for a series of other providers (perhaps eventually replacing it entirely?), but there's still state that it maintains.

This PR moves all the state having to do with the list of payment methods to a new provider, PaymentMethodProvider.

Testing Instructions

Automated tests should handle most things.

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-138696

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-138696&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-138696&env=a8c-for-agencies

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

Sections (~89 bytes added 📈 [gzipped])

Details

name                               parsed_size           gzip_size
site-purchases                          +734 B  (+0.0%)      +89 B  (+0.0%)
purchases                               +734 B  (+0.0%)      +89 B  (+0.0%)
jetpack-cloud-partner-portal            +734 B  (+0.1%)      +89 B  (+0.0%)
checkout                                +734 B  (+0.0%)      +89 B  (+0.0%)
a8c-for-agencies-purchases              +734 B  (+0.1%)      +89 B  (+0.0%)
a8c-for-agencies-client                 +734 B  (+0.1%)      +89 B  (+0.0%)
plans                                   +629 B  (+0.0%)      +74 B  (+0.0%)
jetpack-connect                         +629 B  (+0.1%)      +74 B  (+0.0%)
jetpack-cloud-pricing                   +629 B  (+0.1%)      +74 B  (+0.0%)
jetpack-cloud-plugin-management         +629 B  (+0.0%)      +74 B  (+0.0%)
jetpack-cloud-manage-pricing            +629 B  (+0.2%)      +74 B  (+0.1%)
jetpack-cloud-features-comparison       +629 B  (+0.1%)      +74 B  (+0.0%)
jetpack-cloud-agency-dashboard          +629 B  (+0.1%)      +74 B  (+0.0%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Async-loaded Components (~89 bytes added 📈 [gzipped])

Details

name                                                                              parsed_size           gzip_size
async-load-calypso-blocks-editor-checkout-modal                                        +734 B  (+0.1%)      +89 B  (+0.0%)
async-load-signup-steps-page-picker                                                    +629 B  (+0.2%)      +74 B  (+0.1%)
async-load-purchase-modal-wrapper                                                      +629 B  (+0.2%)      +74 B  (+0.1%)
async-load-my-sites-checkout-purchase-modal-is-eligible-for-one-click-checkou...       +629 B  (+0.2%)      +74 B  (+0.1%)
async-load-masterbar-cart-masterbar-cart-wrapper                                       +629 B  (+0.5%)      +74 B  (+0.2%)

React components that are loaded lazily, when a certain part of UI is displayed for the first time.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• blaze-dashboard
• help-center
• notifications
• odyssey-stats
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug add/payment-method-provider on your sandbox.