Copy items when constructing ClientboundSetCursorItemPacket

Unlike ClientboundContainerSetSlotPacket, the constructor
itself does not copy the item. Thus, we need to pass a copy of
the item to the constructor.

patches/server/1059-Correct-update-cursor.patch

@@ -10,15 +10,15 @@ now leads to an IOOB.
 patch uses instead.
 
 diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
-index d7ac001d53a083e9881f2320eb7fd5dcbd20416e..b5d5dbc50a7b8c40739a15f164ffd08fdc534f9c 100644
+index d7ac001d53a083e9881f2320eb7fd5dcbd20416e..cd1b6b539a62fa5237d6dab2d1c09a2e631d9941 100644
 --- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
 +++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
 @@ -3287,7 +3287,7 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
                                      case PLACE_SOME:
                                      case PLACE_ONE:
                                      case SWAP_WITH_CURSOR:
 -                                        this.player.connection.send(new ClientboundContainerSetSlotPacket(-1, -1, this.player.inventoryMenu.incrementStateId(), this.player.containerMenu.getCarried()));
-+                                        this.player.connection.send(new net.minecraft.network.protocol.game.ClientboundSetCursorItemPacket(this.player.containerMenu.getCarried())); // Paper - correctly set cursor
++                                        this.player.connection.send(new net.minecraft.network.protocol.game.ClientboundSetCursorItemPacket(this.player.containerMenu.getCarried().copy())); // Paper - correctly set cursor
                                          this.player.connection.send(new ClientboundContainerSetSlotPacket(this.player.containerMenu.containerId, this.player.inventoryMenu.incrementStateId(), packet.getSlotNum(), this.player.containerMenu.getSlot(packet.getSlotNum()).getItem()));
                                          break;
                                      // Modified clicked only
@@ -27,7 +27,7 @@ index d7ac001d53a083e9881f2320eb7fd5dcbd20416e..b5d5dbc50a7b8c40739a15f164ffd08f
                                      case DROP_ONE_CURSOR:
                                      case CLONE_STACK:
 -                                        this.player.connection.send(new ClientboundContainerSetSlotPacket(-1, -1, this.player.inventoryMenu.incrementStateId(), this.player.containerMenu.getCarried()));
-+                                        this.player.connection.send(new net.minecraft.network.protocol.game.ClientboundSetCursorItemPacket(this.player.containerMenu.getCarried())); // Paper - correctly set cursor
++                                        this.player.connection.send(new net.minecraft.network.protocol.game.ClientboundSetCursorItemPacket(this.player.containerMenu.getCarried().copy())); // Paper - correctly set cursor
                                          break;
                                      // Nothing
                                      case NOTHING:
@@ -36,7 +36,7 @@ index d7ac001d53a083e9881f2320eb7fd5dcbd20416e..b5d5dbc50a7b8c40739a15f164ffd08f
                      if (packet.slotNum() >= 0) {
                          this.player.connection.send(new ClientboundContainerSetSlotPacket(this.player.inventoryMenu.containerId, this.player.inventoryMenu.incrementStateId(), packet.slotNum(), this.player.inventoryMenu.getSlot(packet.slotNum()).getItem()));
 -                        this.player.connection.send(new ClientboundContainerSetSlotPacket(-1, this.player.inventoryMenu.incrementStateId(), -1, ItemStack.EMPTY));
-+                        this.player.connection.send(new net.minecraft.network.protocol.game.ClientboundSetCursorItemPacket(ItemStack.EMPTY)); // Paper - correctly set cursor
++                        this.player.connection.send(new net.minecraft.network.protocol.game.ClientboundSetCursorItemPacket(ItemStack.EMPTY.copy())); // Paper - correctly set cursor
                      }
                      return;
                  }