I can not even access /usr/local/cpanel/ on my server (which does use cPanel), so I would have to find just where this sa-learn directory is lurking if I wanted to use it. I'm not sure my mail server is even still using SA, as I can not find sa-learn. If your server uses SA, you would need to find where sa-learn is. You can open a ticket to ask, or use shell access or a one-time cron job to search for it:
find / -type d -name "sa-learn" -print 2>/dev/nulland see if anything is returned. If not, there is no sa-learn directory.