banner: fix control config merge behaviour

src/routes/+page.svelte

@@ -84,6 +84,7 @@
 	title="Manage Cookies"
 	controls={{
 		moreInfo: { label: 'More Info', type: 'link', href: '#!' },
+		dismiss: null,
 		swap: true
 	}}
 	onaccept={() => console.log('Cookies accepted!')}