Disallow scrolling the block preview. (#63558)

Author: jasmussen

packages/edit-site/src/components/global-styles/style.scss

@@ -112,9 +112,9 @@
 .edit-site-global-styles__block-preview-panel {
 	position: relative;
 	width: 100%;
-	overflow: auto;
 	border: $gray-200 $border-width solid;
 	border-radius: $radius-block-ui;
+	overflow: hidden;
 }
 
 .edit-site-global-styles__shadow-preview-panel {