Fixes: #9709
Issue link: https://github.com/spring-projects/spring-integration/issues/9709
The Java DSL loses an `inputChannel` when existing channel is referenced by its name.
Then the target IntegrationFlow does not contain a bean reference for this channel and when we call its `getInputChannel()` we got something from middle of the flow.
However, that `inputChannel` is really expected to be an input for the flow.
* Fix `IntegrationFlowBeanPostProcessor` to get a bean by `MessageChannelReference` and populate it into `targetIntegrationComponents`
as we do for newly created `DirectChannel` if there is no bean for provided `MessageChannelReference`
# Conflicts:
# spring-integration-core/src/main/java/org/springframework/integration/dsl/context/IntegrationFlowBeanPostProcessor.java
d8fb02306f