fix(#60): Unsubscribe to basket store after logging out

src/lib/components/SignOut.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-	import { createEventDispatcher } from 'svelte';
+	import { createEventDispatcher, onDestroy } from 'svelte';
 	import { basket, type Basket, type Item } from '$lib/stores/basket.js';
 
 	const dispatch = createEventDispatcher();
@@ -16,6 +16,8 @@
 		localBasket = value;
 	});
 
+	onDestroy(unsubscribe);
+
 	async function signOut() {
 		// TODO use the error from the response
 		const { error } = await supabase.auth.signOut().then(() => {