Improve +error.svelte handling

src/routes/trains/+page.ts

@@ -1,7 +1,6 @@
 import { OwlClient, ApiError, ValidationError, ThrowApiError } from '$lib/owlClient';
 import type { ApiTrainsTrainByHeadcode } from '@owlboard/owlboard-ts';
 import type { PageLoad } from './$types';
-import { error } from '@sveltejs/kit';
 
 export const load: PageLoad = async ({ fetch, url }) => {
 	const headcode = url.searchParams.get('h');