This isn't officially supported. Please see the following GitHub issue:
It's possible to hack something together, but I really wouldn't recommend it because you will have to do it on every upgrade of Kibana (and the solution is likely to change). So I would discourage you from doing that unless it's critical for you to have the logos changed. Also, I am not sure if there are any legal things to consider here.
Apache, Apache Lucene, Apache Hadoop, Hadoop, HDFS and the yellow elephant
logo are trademarks of the
Apache Software Foundation
in the United States and/or other countries.