Bundled Themes: Expand initial block editor support.

A handful of items were missed when adding initial support for the new block editor to bundled themes in [43793]-[43800]. This adds support for those missed items.

Props pento, davidakennedy, laurelfulford.

Merges [43869], [43870], [43871], [43872], [43873], [43874], [43875], [43876] to trunk.

Fixes #45238, #45239, #45240, #45242, #45243, #45244, #45245, #45246.
Built from https://develop.svn.wordpress.org/trunk@44152


git-svn-id: https://core.svn.wordpress.org/trunk@43982 1a063a9b-81f0-0310-95a4-ce76da25c4cd