Add SvelteKit server-side error monitoring instrumentation

[Lms24]

To get error monitoring for the server-side of SvelteKit apps, we need to ensure that all errors are caught:

To wrap the handleError hook, I already created a PoC that we can probably base our implementation on. For now it's enough to export this wrapper to let users add it manually. Later on, we can add auto-wrapping functionality like in NextJS.

### Tasks
- [ ] https://github.com/getsentry/sentry-javascript/pull/7411
- [ ] https://github.com/getsentry/sentry-javascript/pull/7416
- [x] Ensure default integrations capture errors not caught by the `handleError` hook