Spring Stop defining a TaskScheduler bean in WebSocketConfigurationSupport

Affects: 5.3.x

WebSocketConfigurationSupport defines a TaskScheduler bean which causes problems in Boot as using @EnableWebSocket causes auto-configuration of a ThreadPoolTaskScheduler to back off, for example. My feeling is that this a very general contract for something that's more specific and largely an implementation detail. It would be helpful to Boot if Framework's WebSocket support could avoid defining a bean at all for its task scheduler or could use a different, WebSocket-specific type to do so.

While this affects 5.3.x, we think it may be a change that can't be made till 6.0.