[JavaScript] v9

[lforst]

The general topics for this major:

• Very little actual breakage
• API cleanup
• Behaviour cleanup

The items for this major can be found in https://github.com/getsentry/sentry-javascript/issues/14224 (pre-work), https://github.com/getsentry/sentry-javascript/issues/14225 (main work), https://github.com/getsentry/sentry-javascript/issues/14288 (pre-release tasks) and https://github.com/getsentry/sentry-javascript/issues/14226 (post-release tasks).

The following items are likely also gonna happen but need a bit more refinement and have dependencies on stakeholders outside of the JavaScript SDK.

### Needs Refinement
- [ ] https://github.com/getsentry/sentry-javascript/issues/14312
- [ ] https://github.com/getsentry/sentry-javascript/issues/14332

We also include some stretch goals that may get pulled into the major if we deem it valuable:

### Stretch Goals
- [ ] Removing `SyncPromise`
- [ ] https://github.com/getsentry/sentry-javascript/issues/9072
- [ ] https://github.com/getsentry/sentry-javascript/issues/13885
- [ ] https://github.com/getsentry/sentry-javascript/issues/12399
- [ ] Replace `sucrase` with `swc`
- [ ] `requestDataIntegration` improvements
- [ ] Replace instances of `PromiseLike` with `Promise`
- [ ] Default `attachStackTrace` to `true` and add option to disable stack trace attachment for individual `capture*()` calls
- [ ] https://github.com/getsentry/sentry-javascript/issues/11230

[mydea]

Bump minimum Node.js version to 16+

IMHO we can also look into going to 18+. Lots of stuff depends on 18+ 🤔

[AbhiPrasad]

We should re-evaluate our current session code (both server-side with request mode sessions and client-side).

I think we have the opportunity to extract these into integrations to make it more modular, and allow for users to tree-shake out the logic if they don't want it (should save decent bundle size on browser).