audio and video is user driven as per Apple privacy rules..  you can't enabled via PPPC 

jamf-42 is correct. audio and video must be user approved through apple's policies. that said if you ever need the bundle id or code requirement for an app, these commands are helpful:

codesign -dv /path/to/application
codesign -dr - /path/to/application

and also this : https://github.com/jamf/PPPC-Utility

Thanks for the feedback @jamf-42 and @mschlosser.

The issue, which in fact has turned out not to be an issue, is when deploying Slack and a user want to share their screen if prompts for admin permissions, i.e. to add Slack to System Settings >  Privacy & Security > Screen & System Audio Recording. As we hide the local admin user and try not to share account details, I was hoping there was a way of avoiding the admin prompt. As it turns out if the user, i.e. a Standard user, just goes to Screen & System Audio Recording they can manually add the app themselves, i.e. no need for admin privileges.

Hey not sure if I undertstood the issue correctly, but, you just need a PPPC for Slack and set the following setting to "Allow Standard User to Approve", once they try to use screen sharing for example they will be prompted to go to the section in Privacy to allow it, which they should be able to check the box without needing admin rights.