site: fix 404 page by upgrading SvelteKit and avoiding null reference

[benmccann]

will fix 404s sometimes being returned as 500s as discussed in #9116 (comment)

[changeset-bot]

⚠️ No Changeset found

Latest commit: ed30ebb

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[gtm-nayan]

Houston, we have a problem

[benmccann]

gah!! well we might as well upgrade anyway, but yeah it looks like we have something else to fix too

the lint failure is unrelated. I just sent another PR for that: #9338

[benmccann]

I rebased this against master, so the CI is passing now. Let's go ahead and merge this just to be on the latest even if it doesn't fix the issue. We can also test in prod then to see if there was any weird caching going on in the Vercel preview environment or anything like that

[eltigerchino]

Houston, we have a problem

Some thoughts on this issue sveltejs/kit#10565 (comment)
The main cause is a rendering error in the root +layout.svelte while rendering the default error page. #9344

svelte/sites/svelte.dev/src/routes/+layout.svelte

Line 27 in 28d6b34

{#if !$page.route.id.startsWith('/blog/')}

TypeError: Cannot read properties of null (reading 'startsWith')

but the error message being incorrect is a sveltekit issue

[benmccann]

I sent sveltejs/kit#10911 to fix the types in SvelteKit.

And I pushed a commit here to allow the 404 page to render correctly: ed30ebb