I18N: add border.radiusSizes key to theme-i18n.json

Makes border radius size name property translatable by updating `theme.json` i18n schema.

Props hbhalodia, mukesh27, swissspidy, twvania, umeshsinghin, wildworks.
Fixes #64333.

git-svn-id: https://develop.svn.wordpress.org/trunk@61361 602fd350-edb4-49c9-b593-d223f7449a82

Author: t-hamano

src/wp-includes/theme-i18n.json

@@ -52,6 +52,13 @@
 				}
 			]
 		},
+		"border": {
+			"radiusSizes": [
+				{
+					"name": "Border radius size name"
+				}
+			]
+		},
 		"blocks": {
 			"*": {
 				"typography": {
@@ -96,6 +103,13 @@
 							"name": "Space size name"
 						}
 					]
+				},
+				"border": {
+					"radiusSizes": [
+						{
+							"name": "Border radius size name"
+						}
+					]
 				}
 			}
 		}