Teleporting a player doesn't teleport its spectators

The bug

When we use Spectator mode to spectate a player, and that player is teleported, we stay behind, leaving the spectator view of the player. With mobs, on the other hand, the spectator teleports with the mob.

How to reproduce

1. Start a server or LAN world.
2. Spectate a player, and teleport 1000 blocks away.
   → You don't teleport with the player