fix(auth-ui-svelte): make additionalData prop optional (#217)

* fix(svelte): make additionalData prop optional

* Add changeset file to bump the package version

---------

Co-authored-by: Andrew Smith <a.smith@silentworks.co.uk>

Author: sergejcodes

.changeset/tame-mails-act.md

@@ -0,0 +1,5 @@
+---
+'@supabase/auth-ui-svelte': patch
+---
+
+Make additionalData optional by default

packages/svelte/src/lib/Auth/Auth.svelte

@@ -34,7 +34,7 @@
 	export let theme: 'default' | string = 'default';
 	export let localization: { variables?: I18nVariables } = {};
 	export let otpType: OtpType = 'email';
-	export let additionalData: { [key: string]: any } | undefined;
+	export let additionalData: { [key: string]: any } | undefined = undefined;
 
 	onMount(() => {
 		const { data: authListener } = supabaseClient.auth.onAuthStateChange((event) => {