Spring [5.3.x] Fix JettyWebSocketSession.getRemoteAddress throwing instead of returning null with Jetty 10

Add graceful processing of org.eclipse.jetty.websocket.api.Session#getRemoteAddress returning null for Jetty 10 Closes #33619

This PR doesn't need a port to 5.2.x or 6+ branches. 5.2.x and 6.x branches handle this code identically, in a simple way, for two different jetty versions not maintaining compatibility between them. 5.3.x has Jetty 9 and 10 compatibility layer which introduced the problem.

Comment From: pivotal-cla

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Comment From: bclozel

See https://github.com/spring-projects/spring-framework/issues/33619