Update vitest to 1.x

[techniq]

We are currently on vitest 0.33 as we ran into Failed to resolve entry for package "@sveltejs/package" when updating to 0.34 initially. This sounds like it can be solved by adding @sveltejs/vite-plugin-svelte as a direct dependency.

I recently tried to update to the latest 1.2.0 as part of updating to Vite 5 / SvelteKit 2, and ran into fsevent errors. See CI logs on the automated PR to update to 0.34

[techniq]

@dimfeld FYI: Added a new issue to track. I'll take another stab once I ship design tokens / Intl updates, but if you have any ideas, I'm all ears :)

[dimfeld]

A few observations:

• Same results with node 20 or 21
• This isn't related to anything that the test itself is doing. If I run just a single test, the test runs and passes but it hits the esbuild error afterward anyway.
  
• Note that the above works best with one of the shorter tests, since whatever is causing the error seems to be runnign concurrently
• Removing the code coverage functionality makes no difference
• Removing sveld from the vite config makes no difference