Open link control if submenu parent is link. (#34798)

packages/block-library/src/navigation-submenu/edit.js

@@ -354,6 +354,16 @@ export default function NavigationSubmenuEdit( {
 		[ clientId ]
 	);
 
+	// Show the LinkControl on mount if the URL is empty
+	// ( When adding a new menu item)
+	// This can't be done in the useState call because it conflicts
+	// with the autofocus behavior of the BlockListBlock component.
+	useEffect( () => {
+		if ( ! openSubmenusOnClick && ! url ) {
+			setIsLinkOpen( true );
+		}
+	}, [] );
+
 	// Store the colors from context as attributes for rendering
 	useEffect( () => {
 		// This side-effect should not create an undo level as those should