Earn: Add a plans check to the Donations block.

[kwight]

This PR adds a check for a valid plan when inserting the Donations block, and displays a prompt to upgrade if the user is required to do so. Based on the Premium Content block process.

See: #42856

Testing instructions

• On this branch locally, run yarn dev --sync to sync the changes to your sandbox.
• Sandbox the API, and a test site that has no plan.
• On that test site, start a new post at /wp-admin/post-new.php.
• Add a Donations block.
• Verify the Donations block loads with a spinner while making a call to https://public-api.wordpress.com/wpcom/v2/sites/:site_id/memberships/status.
• When the API call completes, the block should display the upgrade prompt.
• Check the API error state by misspelling the endpoint – this should trigger it properly.
• Click the upgrade button and complete the upgrade process for a Personal plan.
• Back in the editor tab, reload the editor.
• Verify the empty Donations tabs display after the network call/spinner display.

[matticbot]

Test live: https://calypso.live/?branch=add/donations-block-plan-upgrade

[kwight]

This doesn't work yet.

[matticbot]

Caution: This PR affects files in the FSE Plugin on WordPress.com
Please ensure your changes work on WordPress.com before merging.

D44610-code has been created so you can easily test it on your sandbox. See this FieldGuide page about developing in the FSE Plugin for more info: PCYsg-ly5-p2

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[kwight]

This should be ready to go. The Stripe prompt and full Donations block functionality will be handled in later PRs.

[gwwar]

Whoops I ran out of time Kirk, the misc notes I added aren't important, I'll go through manual testing steps tomorrow if folks don't beat me to it

[mmtr]

I'm not sure if I'm missing any step, but the upgrade nudge doesn't show up for me when testing on a site not having a paid plan.

Scratch that, I didn't have the branch updated. It works great!

Verified that blocking the request from the dev tools shows a proper message.

Once upgraded, the tabs are displayed as expected.

Also noted multiple requests are fired, likely because we run the effect on every component update. Feel free to land if folks tidy the case, no need for re-review.

[gwwar]

This tests well for me @kwight and should be safe to land. Overall we might want to think about how to make the upgrade flow a little easier for folks, but this is an existing issue for other blocks as well.