Dynamic traversal source does not get updated when graphs created using ConfiguredGraphFactory with gremlin server documentation

Nobody has claimed this yet.

Even with this change #1199, if the janusgraph documentation for starting up gremlin-server is followed as suggested [here](https://docs.janusgraph.org/latest/server.html#_janusgraph_server_as_both_a_websocket_and_http_endpoint). Graph traversal sources does not get updated.

Problem is, the documentation uses `org.apache.tinkerpop.gremlin.server.channel.WsAndHttpChannelizer`. Which does not initialize [this](https://github.com/paul-k-civitas/janusgraph/blob/a918185c8d374c4c49a749c2b9cec3a3162930f5/janusgraph-core/src/main/java/org/janusgraph/graphdb/management/JanusGraphManager.java#L120) thread as its started by [this](https://github.com/paul-k-civitas/janusgraph/blob/a918185c8d374c4c49a749c2b9cec3a3162930f5/janusgraph-server/src/main/java/org/janusgraph/channelizers/JanusGraphWsAndHttpChannelizer.java#L34).

Needs a documentation update, either in [here](https://docs.janusgraph.org/latest/server.html) to use the JanusGaph channelizers or add info [here](https://docs.janusgraph.org/latest/configuredgraphfactory.html)

Start by reading the server.html and configuredgraphfactory.html documentation sections and compare their channelizer guidance with the referenced JanusGraphWsAndHttpChannelizer and WsAndHttpChannelizer classes. Confirm which documented setup initializes dynamic traversal-source updates, then update the relevant documentation so the required channelizer choice or configuration is explicit.

Written by the indexing model from the issue text.