Please find the steps (and screenshots attached) on how to enable Automatic-App updates on Android TV.

1. Open 'Play Store' app

2. Select 'Settings' from the left-navigation panel

3. Select 'Auto Update Apps'

4. Select 'Auto Update Apps at Any time'

Kindly note that since the auto-update feature works only via the Play Store itself. 

Therefore this can only be verified when there is a pending app update to be installed via Play Store.