Fixes https://github.com/spring-projects/spring-integration/issues/3026 **Cherry-pick to `5.1.x`** * Populate proper `FileTransferringMessageHandler` impl from DSL spec implementations. This way we are able to use a provided `chmod` from Java DSL * Added `FileTransferringMessageHandlerSpec` ctor TODO * Update SftpTests * Code cleanup; `@Ignore` `SftpTests.testSftpOutboundFlowWithChmod()` since it doesn't work properly on Windows