Remove unused .drawer-content-horizontal class from styles

Refs: #7487

Author: deleonio

packages/samples/react/src/style.scss

@@ -52,10 +52,6 @@ hr {
 	width: rem(400);
 }
 
-.drawer-content-horizontal {
-	height: rem(400);
-}
-
 @media (min-width: 1024px) {
 	.app-container {
 		display: grid;
@@ -92,4 +88,4 @@ hr {
 	.no-print * {
 		display: none !important;
 	}
-}
+}