* Fix dynamic Websocket endpoints for SockJS
Related to https://stackoverflow.com/questions/67971467/registration-of-dynamic-websocket-at-application-initialization-time-and-at-runt
The SockJS wrapper for dynamic endpoint is not initialized properly.
Technically we just don't map to the SockJS service if such one is requested from the `ServerWebSocketContainer` configuration
* Postpone the path mapping for the target endpoint until after the `ServerWebSocketContainer` applies all the options
into its registration to expose.
* Fix `ServerWebSocketContainer` to propagate a default `TaskScheduler` for underlying SockJS Service on the endpoint
* Fix `IntegrationDynamicWebSocketHandlerMapping` to deal with path patterns as well, which is the case for the mentioned SockJS wrapper:
the SockJS Service is able to handle the rest of the path according its setting and request requirements
* * Fix unused imports
* Add Javadoc for new `ServerWebSocketContainer.setSockJsTaskScheduler()` API
* * Cover SockJS server configuration in the WebSocketDslTests
93743f69fe