Purchases: Reduxify notices in payment method forms

[tyxla]

Changes proposed in this Pull Request

This PR reduxifies notices in PaymentMethodForm.

Note: This updates both the "add" and "update" functionality, but the "update" functionality is not in-use since this component is in the process of being removed.

Testing instructions

• Go to /purchases. (Note: this will not work if you test /me/purchases since that uses a different component.)
• Click on "Payment methods" in the header navigation.
• Click the "Add payment method" button in the header.
• Add a new credit card and verify that you see a success message.

Part of #48408.

[matticbot]

Test live: https://calypso.live/?branch=reduxify/purchases-payment-method-notices

[matticbot]

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

Sections (~5 bytes added 📈 [gzipped])

name            parsed_size           gzip_size
woocommerce           +76 B  (+0.0%)      +11 B  (+0.0%)
site-purchases        +76 B  (+0.0%)       -6 B  (-0.0%)
purchases             +76 B  (+0.0%)       -6 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.

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.

[sirbrillig]

Thanks! I'll test it out soon. The reason this may seem tricky to test is because we're in the process of removing PaymentMethodForm so I may delay on this a bit over other PRs.

[tyxla]

Thanks, @sirbrillig. I've rebased in the meantime. This seems to be a bit easier to review now, partially because some of the code doesn't seem to be used anywhere 😉

[tyxla]

@sirbrillig what can I do to help escalate this PR? It seems to be the last one that blocks the removal of the good ol' notices library.

[sirbrillig]

I updated the testing instructions because this is tricky to test. Notably, this component is not used at the account-level, only the site-level, so I changed the URL to /purchases; also the "update" functionality is no longer in use anywhere, so I removed that test case.

Works as described!

[tyxla]

Thanks a bunch, @sirbrillig 🙌