CAMEL-24069: camel-spring-rabbitmq - Use consumer exception handler for async failures

When asyncConsumer=true and an exchange fails after the listener method
returns, the failure was silently dropped because endpoint.getExceptionHandler()
is null by default. Use consumer.getExceptionHandler() instead, which always
has a default LoggingExceptionHandler.

Closes #24721

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: davsclaus

components/camel-spring-parent/camel-spring-rabbitmq/src/main/java/org/apache/camel/component/springrabbit/EndpointMessageListener.java

@@ -251,10 +251,8 @@ public void done(boolean doneSync) {
                     // method and rethrow it
                     exchange.setException(rce);
                 } else {
-                    // we were done async, so use the endpoint error handler
-                    if (endpoint.getExceptionHandler() != null) {
-                        endpoint.getExceptionHandler().handleException(rce);
-                    }
+                    // we were done async, so use the consumer error handler
+                    consumer.getExceptionHandler().handleException("Error processing exchange", exchange, rce);
                 }
             }