asynchronous HTTP send and receive

**Citrus Version**
4.0.0-M2

**Question**
1) Expecting that the HttpServer to send a Response back to the HttpClient (with specified content) when it receives a message from the HttpClient.
2) setting `citrus.html.report.directory=build/citrus-reports` does moves one file `citrus-test-results.html` to the build directory but the **junitreports** still gets generated in the **target** directory: `target/citrus-reports/junitreports/TEST-TestSuite.xml`

**What I've tried so far**
Have a reproducible code attached. Looks like it is sending a default empty message.
Use case is that our IT test will call our application through HTTP, our application needs to call one or more backends (this HttpServer) and we want to send back a response back to the application.

**Additional information**
See attachment:
[example-http-server-issue.zip](https://github.com/citrusframework/citrus/files/12609853/example-http-server-issue.zip)
Example build with gradle and kotlin and using JUnit5

Start with the attached example-http-server-issue.zip and its Gradle/Kotlin JUnit5 reproduction. Trace the asynchronous HttpServer request and response flow, then inspect where HTML and JUnit reports choose their output directories. Done means the configured response content reaches the client and junitreports is generated under the configured build directory.

Written by the indexing model from the issue text.