Remove APIs deprecated for removal in 6.2

[sbrannen]

Remove APIs that have been "deprecated for removal in 6.2".

Candidates

• org.springframework.util.Base64Utils
• org.springframework.cache.jcache.interceptor.JCacheOperationSourcePointcut
• org.springframework.http.client.AbstractClientHttpResponse
• org.springframework.http.client.ClientHttpResponse.getRawStatusCode()
• org.springframework.http.client.observation.ClientHttpObservationDocumentation.HighCardinalityKeyNames.CLIENT_NAME
• org.springframework.web.reactive.function.client.ClientHttpObservationDocumentation.HighCardinalityKeyNames.CLIENT_NAME
• org.springframework.web.filter.reactive.ServerWebExchangeContextFilter.get(Context)
• org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler.handleBindException(BindException, HttpHeaders, HttpStatusCode, WebRequest)
• org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleBindException(BindException, HttpServletRequest, HttpServletResponse, Object)
• org.springframework.web.reactive.HandlerResult.setExceptionHandler
• org.springframework.web.reactive.HandlerResult.hasExceptionHandler
• org.springframework.web.reactive.HandlerResult.applyExceptionHandler
• org.springframework.web.reactive.socket.client.JettyWebSocketClient
• org.springframework.web.socket.client.jetty.JettyWebSocketClient

[2024-11-22] Update:

Both JettyWebSocketClient variants were actually removed earlier, in 6.1 as part of the upgrade to Jetty 12, see #30698 and #29576. However, the work to re-implement Jetty support in WebFlux re-introduced a Jetty 12 based client in Spring WebFlux in 6.2, see #32097.