Layout Support: Replace incremental IDs with hashes

[DAreRodz]

This is a backport PR for WordPress 6.8 that includes the following PHP Gutenberg changes:

• Layout Support: Replace incremental IDs with hashes gutenberg#68210

Trac ticket: https://core.trac.wordpress.org/ticket/62985

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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.

[github-actions]

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[github-actions]

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Props darerodz, joemcgill.

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[joemcgill]

The code and additional tests look good to me.

It would be nice to add some addition test coverage specifically for the new wp_unique_id_from_values() function, similar to this test class, but I don't see that as a requirement for fixing the bug here.

[DAreRodz]

Thanks, @joemcgill, for your review. 🙏

I'm adding tests for the wp_unique_id_from_values() function. They should be ready before these changes are merged.

[DAreRodz]

@joemcgill, I just added PHPUnit tests for wp_unique_id_from_values() if you want to take a look.

[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 60038
GitHub commit: 8b632c9

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.