Consider disabling usage of `SentryReactorThreadLocalAccessor` if OpenTelemetry is used

### Description

`SentryReactorThreadLocalAccessor` should not be necessary if OpenTelemetry is used for scope propagation through its `Context` instead of relying on our own `ThreadLocal`.

Also see https://github.com/getsentry/sentry-java/issues/4806

We could skip using `SentryReactorUtils` in WebFlux if OpenTelemetry is being used, unless `sentry.reactive.thread-local-accessor-enabled` is set to `true`.