Blocks: update support from __experimentalLayout to layout

[jeherve]

Fixes #32853

Proposed changes:

Related PR where the changes were introduced to Gutenberg:
WordPress/gutenberg#51434

Marks __experimentalLayout, __experimentalLayoutStyle, __experimentalUseLayoutClasses and __experimentalUseLayoutStyles stable.

Block support for layout has now graduated from experimental to stable. Everything works the same; the only difference is that when adding block support for layout in block.json, its name is now layout instead of __experimentalLayout.

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?
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Jetpack product discussion

Primary issue: #32865

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

• No

Testing instructions:

• Test the impacted blocks and ensure they continue to work as expected.

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[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 update/block-layout-support branch.

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[monsieur-z]

LGTM! Blocks look like they do on trunk and I'm not seeing errors in the console.