[Multiplayer] Inventory player preview plays animations from other players

In multiplayer, the player preview shown in the inventory screen behaves incorrectly. Instead of staying mostly static—only turning the head slightly towards the mouse—it starts playing movement and hand animations that appear to be copied from another player in the world. This issue does not happen in singleplayer.

Additionally, when the player is sleeping in a bed, the first-person hand model randomly scales up and down, causing the held item or block to visually change size erratically.