Support Sveltekit v2

[AbhiPrasad]

https://svelte.dev/blog/sveltekit-2

https://kit.svelte.dev/docs/migrating-to-sveltekit-2

### Necessary for Kit 2.0
- [ ] https://github.com/getsentry/sentry-javascript/pull/9861
- [ ] https://github.com/getsentry/sentry-javascript/pull/9872
- [ ] https://github.com/getsentry/sentry-javascript/pull/9873
- [ ] https://github.com/getsentry/sentry-javascript/pull/9901
- [ ] https://github.com/getsentry/sentry-javascript/pull/9902

Not necessary for initial kit 2.x support but nice to have eventually:

• Use new untrack utility function when available #9911
• Use new handleLoad hook when released and available #9912

[wesbos]

Our migration is here syntaxfm/website#1458 if you need us to test anything

[Lms24]

Added a few tasks to investigate from reading the migration guide and a few PRs

[Lms24]

Something to follow up on which hasn't yet landed - handle(Server)Load hooks: sveltejs/kit#11313

My first take: When this lands, we export handlers for it from our SDK but continue with auto instrumentation. In v9 we drop 1.x support, remove auto instrumentation and switch to exclusively instrumenting load functions via handle(Server)Load. If we adjust the wizard to add the handlers automatically at this point, I believe we should be good.

[Lms24]

Closing this issue as all necessary 2.x tasks were completed. We're going to release 7.89.0 in the next hours which will include all PRs linked above.

if you experience any after upgrading to sveltekit 2.x please let us know and open a new issue, thank you!