Regression - NIO TcpConnectionOpenEvent published to early

Introduced when we added connection timeout support: https://github.com/spring-projects/spring-integration/commit/466daa8774c8da78a971b48d096659a9c1f08524#diff-c5b8d701d6369ca2fed8cbb0f8086eab

https://stackoverflow.com/questions/62291284/triggering-actions-upon-clientconnectionfactory-connection-establishment-accep