Feature: Offline donations gateway v3 compatibility

[JasonTheAdams]

Description

This PR is a rebuild of the Offline gateway to make use of the Gateway API and be v2 + v3 compatible. It cleans up a bunch of the old code and should port everything over nicely. The ID and everything should be preserved such that it's full backwards-compatible.

Note, since there's now a Billing Address block, the billing address settings don't do anything anymore on v3 forms. It should still work on v2 forms, though.

Affects

The offline donations gateway

Visuals

In the donation form

Settings in form builder

Testing Instructions

Make sure the Offline gateway works with v2 and v3 forms. Make sure to test out the various settings and emails related to offline.

Pre-review Checklist

• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed

[JasonTheAdams]

@jonwaldstein This is ready for review! Happy to hop on a call to review together if you feel that would speed things up.

[jonwaldstein]

@JasonTheAdams i'm getting a bunch of errors when running npm run dev. If you added a typescript package to support an existing package - the versions need to match up or else the types are coming from a different version.

[JasonTheAdams]

@jonwaldstein Are you able to help with that? How do I know which version to use?

[jonwaldstein]

@jonwaldstein Are you able to help with that? How do I know which version to use?

The version of the @types/{package} and the actual {package} need to be as close as possible - since the @types/{package} is basically supplying types for that version of the package.

Yes I can help

[jonwaldstein]

@JasonTheAdams fyi there's some discrepencies between the latest @types/wordpress__block-editor version and @wordpress/block-editor - they're not in sync at the moment so removing for now. we can solve this another time.

[jonwaldstein]

Looking good, left a few comments. You will also want to add a migration for the form settings to block attributes.

[JasonTheAdams]

@jonwaldstein Your appreciated feedback has been addressed and (thanks to your guard suggestion) all tests are passing. This is ready for another review!

[jonwaldstein]

@JasonTheAdams are you going to update this PR with the migration as well?

[JasonTheAdams]

@JasonTheAdams are you going to update this PR with the migration as well?

Ah yes, good point! I'll do that now!

[JasonTheAdams]

@jonwaldstein I added the migration code: 22fff11

[jonwaldstein]

Nice job! ready for QA 💸

[rickalday]

Passed manual QA tests.