fix: support instrumentation for `vite preview` (#15105)

fix: support instrumentation for `vite preview` (#15105)

The `instrumentation.server.js` file is now imported when running
`vite preview`. Unfortunately, since it's not the first thing that's
imported (all of Vite's depedencies are imported first), some
instrumentation that rely on monkey-patching imports might not work
properly, but at least we're importing it before the server code.
However, this matches the existing behaviour of `vite dev`.

See: https://github.com/sveltejs/kit/blob/51214794b40b2fc533b06cb8344e84e661f90be0/packages/kit/src/exports/vite/dev/index.js#L507-L513