Nix some client-sided sounds, control them from the server

this is a necessary step to knock out the implicit assumption that every player is using the same protocol.

src/world/sound/EntityShortFallSound.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\world\sound;
+
+use pocketmine\entity\Entity;
+use pocketmine\math\Vector3;
+use pocketmine\network\mcpe\protocol\AddActorPacket;
+use pocketmine\network\mcpe\protocol\LevelSoundEventPacket;
+use pocketmine\player\Player;
+
+/**
+ * Played when an entity hits the ground after falling a short distance.
+ */
+class EntityShortFallSound implements Sound{
+
+	/** @var Entity */
+	private $entity;
+
+	public function __construct(Entity $entity){
+		$this->entity = $entity;
+	}
+
+	public function encode(?Vector3 $pos){
+		return LevelSoundEventPacket::create(
+			LevelSoundEventPacket::SOUND_FALL_SMALL,
+			$pos,
+			-1,
+			$this->entity instanceof Player ? "minecraft:player" : AddActorPacket::LEGACY_ID_MAP_BC[$this->entity::NETWORK_ID] //TODO: bad hack, stuff depends on players having a -1 network ID :(
+			//TODO: does isBaby have any relevance here?
+		);
+	}
+}