Keep the sidebar border

packages/edit-post/src/style.scss

@@ -77,18 +77,3 @@ body.js.block-editor-page {
 }
 
 @include wordpress-admin-schemes();
-
-// The edit-site package adds or removes the sidebar when it's opened or closed.
-// The edit-post package, however, always has the sidebar in the canvas.
-// These edit-post specific rules ensures there isn't a border on the right of
-// the canvas when a sidebar is visually closed.
-.interface-interface-skeleton__sidebar {
-	border-left: none;
-
-	.is-sidebar-opened & {
-		@include break-medium() {
-			border-left: $border-width solid $gray-200;
-			overflow: hidden scroll;
-		}
-	}
-}