Fixes https://github.com/spring-projects/spring-integration/issues/8664 When an `Observation` is turned to `NoopObservation`, the `observeWithContext()` fails with `ClassCastException` since `NoopObservation` serves just plain `Context` not the one we supplied * Fix `MessagingGatewaySupport.sendAndReceiveWithObservation()` same way as it is in version `6.0.x` * Modify `IntegrationObservabilityZipkinTests` to reject some `Observation` via `observationPredicate()` configuration **Cherry-pick to `6.1.x`**