CLI commands like "user roles ...." which require a connection are partially shown with tab-completion.
But the command fail with error if it is in state disconnected.

Current behavior:
[disconnected]> user -> <tab>
create describe encrypt-all groups ls password remove
[disconnected]> user roles -> <tab>
create deny grant ls remove
[disconnected]> user roles ls
Cannot invoke "org.infinispan.cli.connection.Connection.execute(java.util.function.BiFunction, org.infinispan.cli.connection.Connection$ResponseMode)" because the return value of "org.infinispan.cli.Context.getConnection()" is null

Expected behavior:
<tab> should not show further options for commands which are not available.
If the command is typed it should end in a message like shown below for the backup command
[disconnected]> backup
The command is not available in the current context.