Fix content type response for ActivityPub
Fix content type response for ActivityPub

Chocobozzz/PeerTube,Green-Star/PeerTube,Green-Star/PeerTube,Chocobozzz/PeerTube,Chocobozzz/PeerTube,Green-Star/PeerTube,Green-Star/PeerTube,Chocobozzz/PeerTube