MINOR: Clean Javadoc for BrokerReconfigurable interface (#20593)

Reviewers: Mickael Maison <[email protected]>, TengYao Chi <[email protected]>

Author: sjhajharia

server-common/src/main/java/org/apache/kafka/config/BrokerReconfigurable.java

@@ -32,7 +32,6 @@
  *   <li>Validating the new configuration before applying it via {@link #validateReconfiguration(AbstractConfig)}</li>
  *   <li>Applying the new configuration via {@link #reconfigure(AbstractConfig, AbstractConfig)}</li>
  * </ol>
- * <strong>Note: Since Kafka is eliminating Scala, developers should implement this interface instead of {@link kafka.server.BrokerReconfigurable}</strong>
  */
 public interface BrokerReconfigurable {
     /**