Subscriptions: allow pre-selecting newsletter categories in block settings

[holdercp]

Closes Automattic/loop#378

New to block development and Jetpack so please review with a critical eye.

Proposed changes:

• Adds new options in the Subscriptions block settings that will allow site owners to select newsletter categories that this subscription form will automatically subscribe users to
• These selected categories will be exposed to the subscription form so the category selection modal can be bypassed when this new option is enabled

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

• pe7F0s-2tV-p2 (current project)
• pe7F0s-2t7-p2 (abandoned project but has some of the discussion around this change)

Does this pull request change what data or activity we track or use?

Testing instructions:

• Follow documentation to checkout this branch on your sandbox
• Enable Newsletter Categories for your site and add a few
• Add a Subscribe block to a post
• In the Subscribe settings sidebar, under Settings, verify the new "Pre-select Categories" toggle works as expected
  • If enabled, you should be able to selected specific categories for the block
  • If disabled, you should not be able selected specific categories (they should clear if some were selected)
  • Make sure when you save the block and visit it again the settings persist
• These block settings have no effect currently but you can verify the correct category ids are being selected by examining the markup from the block. There will be a hidden input with the selected ids named selected_newsletter_categories

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the add/newsletter-cats-to-sub-block branch.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack add/newsletter-cats-to-sub-block
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

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[github-actions]

Code Coverage Summary

Coverage changed in 5 files.

File	Coverage	Δ%	Δ Uncovered
projects/plugins/jetpack/extensions/blocks/subscriptions/subscriptions.php	10/622 (1.61%)	-0.01%	4 💔
projects/plugins/jetpack/extensions/blocks/subscriptions/controls.js	16/21 (76.19%)	1.19%	1 💔
projects/plugins/jetpack/extensions/blocks/subscriptions/view.js	0/43 (0.00%)	0.00%	1 💔
projects/plugins/jetpack/extensions/blocks/subscriptions/edit.js	45/54 (83.33%)	0.98%	0 💚
projects/plugins/jetpack/extensions/store/membership-products/resolvers.js	65/106 (61.32%)	8.49%	-9 💚

Full summary · PHP report · JS report

[holdercp]

This will need to be released after backend changes are in place. Leaving as draft for now but I would love a review to catch any obvious issues that will need to be addressed.