fix buttons missing type="button"

Triggers unintentional form submits if missing `type` property.

src/lib/Dialog.svelte

@@ -219,6 +219,7 @@
 				{/if}
 			</div>
 			<button
+				type="button"
 				aria-label="close"
 				class="absolute top-4 right-4 inline-flex cursor-pointer items-center
 				justify-center disabled:cursor-not-allowed disabled:opacity-50"