Add the spacing for horizontal and vertical for block gap on buttons …

…block (#64971)

Co-authored-by: hbhalodia <hbhalodia@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>
Co-authored-by: andrewserong <andrewserong@git.wordpress.org>
Co-authored-by: jasmussen <joen@git.wordpress.org>
Co-authored-by: AKSHAT2802 <akshat2802@git.wordpress.org>
Co-authored-by: Nyiriland <nyiriland@git.wordpress.org>

packages/block-library/src/buttons/block.json

@@ -21,7 +21,7 @@
 			}
 		},
 		"spacing": {
-			"blockGap": true,
+			"blockGap": [ "horizontal", "vertical" ],
 			"padding": true,
 			"margin": [ "top", "bottom" ],
 			"__experimentalDefaultControls": {