Avoid duplicate loading of configuration classes

[christophd]

Citrus Version
4.0.0

When loading Citrus components via configuration class make sure to not load configurations multiple times. It leads to port binding conflicts for server components.

@CitrusConfiguration(classes = { CitrusEndpointConfig.class })
public class SomeCitrusTest {
 ...
}

The CitrusEndpointConfig.class should be parsed only once for the given Citrus instance. Depending on the underlying unit test framework and setup it may happen that the config class is parsed multiple times (e.g. when running the tests with Quarkus test extension for JUnit5).

Make sure to load Citrus configuration classes in an idempotent way.