fix(ui5-menu): include icon (#9413)

Add icon import, as the icon is currently not showing.

packages/main/src/MenuItem.ts

@@ -5,6 +5,7 @@ import { getI18nBundle } from "@ui5/webcomponents-base/dist/i18nBundle.js";
 import { isPhone } from "@ui5/webcomponents-base/dist/Device.js";
 import AriaHasPopup from "@ui5/webcomponents-base/dist/types/AriaHasPopup.js";
 import type { AccessibilityAttributes } from "@ui5/webcomponents-base/dist/types.js";
+import "@ui5/webcomponents-icons/dist/nav-back.js";
 import type { ListItemAccessibilityAttributes } from "./ListItem.js";
 import ListItem from "./ListItem.js";
 import ResponsivePopover from "./ResponsivePopover.js";