Spring Boot `@AutoConfiguration` comes now with a `proxyBeanMethods = false`,
so we cannot call bean methods within the same configuration class.
* Rework `HeaderEnricherFunctionConfiguration` for bean methods autowiring
* Create an `ExpressionEvaluatingHeaderValueMessageProcessor` instances directly
in the `headerEnricher` bean definition and propagate an injected `BeanFactory`
* Re-enable disabled tests
Fixes#369
0f7488f84c