Fixes https://github.com/spring-projects/spring-integration/issues/8785
The `ClientWebSocketContainer.start()` delegates to the `IntegrationWebSocketConnectionManager`
which performs an async connection to the server.
* Wait for `connectionLatch` in the `ClientWebSocketContainer.start()`
and check for `this.openConnectionException != null` to re-throw.
Mark `ClientWebSocketContainer` as stopped in that case
**Cherry-pick to `6.1.x` & `6.0.x`**
# Conflicts:
# spring-integration-websocket/src/main/java/org/springframework/integration/websocket/ClientWebSocketContainer.java
59df2b9110