Fixes: https://github.com/spring-projects/spring-integration/issues/9792
The `StreamTransformer` closes `IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE` header value,
so this becomes unusable afterward.
In addition, it may even cause some problems downstream when the message could be serialized for
subsequent network interaction.
* Add logic to the `StreamTransformer` to build a new message, but remove `IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE` header
* Verify that header is removed in the `StreamingInboundTests`.
Addition `StreamingInboundTests` clean up for better code style.
8dab7409b5