Add $schema to block and theme JSON

[sirreal]

Add $schema to block.json and theme.json files.

Note that not all files are valid according to the schema. I'm working on those fixes in WordPress/gutenberg#57374 and will port those changes when they're finished.

Some of the invalid (according to the schema) block and theme json files are in phpunit tests were invalid due to missing title properties. In those cases I've fixed the json to satisfy the schema. Those changes have no impact on the runtime whatsoever and do not change the result of unit tests.

This is a port of WordPress/gutenberg#57201

Trac ticket: https://core.trac.wordpress.org/ticket/60255

Add $schema to block.json and theme.json files to leverage JSON schema support.

Schemas help ensure that these files conform to expectations. They can help provide autocomplete and documentation if editors are configured to do so.

We provide and maintain these schemas, we should be using them. This can help to ensure that our own declarations are correct and that the schemas are also correct.

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[gziolo]

https://github.com/WordPress/wordpress-develop/actions/runs/7529540433/job/20493970875?pr=5868

Files in src/wp-includes/blocks are synced from npm packages so they will get updated next time WordPress packages get updated.

[sirreal]

Good to know, thanks! I reverted the changes to src/wp-includes/blocks.

[github-actions]

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[dmsnell]

@sirreal it looks like some of these should come over through the normal package update process? do you know if this is true?

[sirreal]

src/wp-includes/blocks changes should be updated automatically (#5868 (comment)) - I had changed those files but reverted the changes.

[ockham]

I've taken the liberty of slightly tweaking the test hooked blocks' names in 126b31b. Hope that's okay! 😊

[sirreal]

Looks good, thanks @ockham.

[ockham]

Committed to Core in https://core.trac.wordpress.org/changeset/57336.