Button Block: Apply Stretch Styles Correctly (#64770)

Unlinked contributors: joecsmalley.

Co-authored-by: t-hamano <wildworks@git.wordpress.org>
Co-authored-by: tellthemachines <isabel_brison@git.wordpress.org>
Co-authored-by: jasmussen <joen@git.wordpress.org>
Co-authored-by: ethanclevenger91 <eclev91@git.wordpress.org>
Co-authored-by: jordesign <jordesign@git.wordpress.org>
Co-authored-by: jennydupuy <jdy68@git.wordpress.org>

Author: 6 people

packages/block-library/src/button/style.scss

@@ -9,6 +9,9 @@ $blocks-block__margin: 0.5em;
 	text-align: center;
 	word-break: break-word; // overflow-wrap doesn't work well if a link is wrapped in the div, so use word-break here.
 	box-sizing: border-box;
+	height: 100%;
+	width: 100%;
+	align-content: center;
 
 	&.aligncenter {
 		text-align: center;