I don't believe this option exists.
Click on Clients >> Click the Group you want to modify >> Click on the Policies tab at the top >> Click General Settings
Under Restart Options you will only have 'Prompt the user to restart the computer' and 'Force the computer restart'
What you could do is enter a generic message such as 'SEP successfully installed' and set 'The notification window will automatically close after (seconds):' to 10 seconds, which is the lowest it will go.
You can also set 'Maximum number of snooze opportunities:' to 0 and do the same for 'Maximum time between snoozes (minutes):' Setting to 0 should turn them off
You may want to test this on one machine before putting into production.
Also, I'm assuming you created and exported a package for deployment?
If so, what type of install package did you create? Silent? Unattended? Interactive? Try deploying a 'Silent' package and see what happens.