Facebook can only listen to audio if you give it microphone permission, and even then the iOS 14 beta would have made it visible if they were turning the mic on

Facebook can only listen to audio if you give it microphone permission, and even then the iOS 14 beta would have made it visible if they were turning the mic on when they shouldn't be. Even if they make you install the app they aren't using it to passively listen for ultrasonic signals from your television.