[v8] Merge `@sentry-internal/tracing` into `@sentry/core`

[mydea]

In v8, let's merge tracing-internals into core, and stop publishing @sentry-internal/tracing.

### Tasks
- [ ] https://github.com/getsentry/sentry-javascript/issues/8796
- [ ] https://github.com/getsentry/sentry-javascript/pull/10625
- [ ] https://github.com/getsentry/sentry-javascript/pull/10917
- [ ] https://github.com/getsentry/sentry-javascript/pull/10918
- [ ] https://github.com/getsentry/sentry-javascript/pull/10919
- [ ] https://github.com/getsentry/sentry-javascript/pull/11240
- [ ] https://github.com/getsentry/sentry-javascript/pull/11484