cli: session list are now only get when necessary.

This avoid to reload configuration twice in tmux mode.
3 jobs for config_reload_twice in 2 minutes and 38 seconds
Status Job ID Name Coverage
  Style
passed #47960
check_style

00:00:18

 
  Build
passed #47961
create_doc:reference

00:02:20

passed #47962
create_doc:user

00:02:02