Editor: Update WordPress packages to use with WordPress 5.8

In the response to the discussion during the Dev Chat, I'm doing a first pass to keep WordPress packages up to date in the WordPress 5.8 release cycle.

See https://github.com/WordPress/wordpress-develop/pull/1176 for more details.

Props youknowriad, aristath, andraganescu.
See #52991.


Built from https://develop.svn.wordpress.org/trunk@50761


git-svn-id: http://core.svn.wordpress.org/trunk@50370 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/blocks/search/block.json

@@ -34,6 +34,10 @@
 	},
 	"supports": {
 		"align": [ "left", "center", "right" ],
+		"__experimentalBorder": {
+			"radius": true,
+			"__experimentalSkipSerialization": true
+		},
 		"html": false
 	},
 	"editorStyle": "wp-block-search-editor",