Added TeleportCause for /tp <x> <y> <z>

Currently, when teleporting with /tp <x> <y> <z>, the TeleportCause is not set, e.g. the default value is used instead of the expected TeleportCause.COMMAND. With the /tp <player1> <player2> syntax, the TeleportCause is already correctly set to TeleportCause.COMMAND.