Extract this to C:\Program Files (x86)\Steam\steamapps\common\Sid Meier's Civilization VI\DLC\Expansion2\platforms\windows\audio and replace (or if your Civ is installed on a different drive/folder, modify accordingly). These are just empty files and you might want to replace the sounds with a different sound instead, so you can hear if someone's attacking you with indie bands.
If you want the sounds back, either make backups or just delete the files and use Steam's "verify integrity of game files" option.