quarkus: Reactive Messaging: Tombstone-messages no longer accepted

Describe the bug

Since Quarkus 2.14.0.Final, I can no longer send messages with null-value over the Emitter. I get this exception:

2023-02-08 14:21:13,807 ERROR [io.sma.rea.mes.kafka] (Quarkus Main Thread) SRMSG18207: Unable to dispatch message to Kafka: java.lang.IllegalArgumentException: `payload` must not be `null`
	at org.eclipse.microprofile.reactive.messaging.Message.of(Message.java:304)
	at org.eclipse.microprofile.reactive.messaging.Message.addMetadata(Message.java:532)
	at io.quarkus.opentelemetry.runtime.tracing.intrumentation.reactivemessaging.ReactiveMessagingTracingDecorator.lambda$decorate$1(ReactiveMessagingTracingDecorator.java:75)
	at io.smallrye.context.impl.wrappers.SlowContextualFunction.apply(SlowContextualFunction.java:21)
	at io.smallrye.mutiny.operators.multi.MultiMapOp$MapProcessor.onItem(MultiMapOp.java:42)
	at io.smallrye.mutiny.operators.multi.MultiOperatorProcessor.onItem(MultiOperatorProcessor.java:100)
	at io.smallrye.mutiny.operators.multi.builders.BufferItemMultiEmitter.drain(BufferItemMultiEmitter.java:118)
	at io.smallrye.mutiny.operators.multi.builders.BufferItemMultiEmitter.emit(BufferItemMultiEmitter.java:34)
	at io.smallrye.mutiny.operators.multi.builders.SerializedMultiEmitter.onItem(SerializedMultiEmitter.java:51)
	at io.smallrye.mutiny.operators.multi.builders.SerializedMultiEmitter.emit(SerializedMultiEmitter.java:141)
	at io.smallrye.reactive.messaging.providers.extension.ThrowingEmitter.emit(ThrowingEmitter.java:63)
	at io.smallrye.reactive.messaging.providers.extension.AbstractEmitter.emit(AbstractEmitter.java:164)
	at io.smallrye.reactive.messaging.providers.extension.EmitterImpl.send(EmitterImpl.java:47)
	at org.acme.TestEmitter.emit(TestEmitter.java:46)
	at org.acme.TestEmitter.atStartup(TestEmitter.java:29)
	at org.acme.TestEmitter_Observer_atStartup_0f975a6ffd0cd0e4d2a55a386da871634c38d3e9.notify(Unknown Source)
	at io.quarkus.arc.impl.EventImpl$Notifier.notifyObservers(EventImpl.java:328)
	at io.quarkus.arc.impl.EventImpl$Notifier.notify(EventImpl.java:310)
	at io.quarkus.arc.impl.EventImpl.fire(EventImpl.java:78)
	at io.quarkus.arc.runtime.ArcRecorder.fireLifecycleEvent(ArcRecorder.java:131)
	at io.quarkus.arc.runtime.ArcRecorder.handleLifecycleEvents(ArcRecorder.java:100)
	at io.quarkus.deployment.steps.LifecycleEventsBuildStep$startupEvent1144526294.deploy_0(Unknown Source)

As far as I can see, this happens since ReactiveMessagingTracingDecorator was introduced. This class tries to add a header and therefore rebuilds the message.

Expected behavior

It should be possible to send messages with null-value (tombstone-messages).

Actual behavior

It is not possible to send tombstone-messages.

How to Reproduce?

Reproducer: empty-value-reproducer.zip

1. Execute reproducer
2. Wait a few seconds
3. See exception

Output of uname -a or ver

Microsoft Windows [Version 10.0.19044.2006]

Output of java -version

OpenJDK Runtime Environment Corretto-17.0.4.9.1 (build 17.0.4.1+9-LTS)

GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.16.1.Final

Build tool (ie. output of mvnw --version or gradlew --version)

Apache Maven 3.8.6

Additional information

No response