Let hosts handle exiles

Let hosts handle exiles

Previously Impostor liked to kill exiled players server side to raise an
event. This is quite early, as the host will SetRole them to a ghost
role later.

However as PlayerInfo is server-owned by default in 2024.6.18, it starts
killing players client side. This caused meetings to immediately
conclude if the final impostor was voted out, ruining the cutscene.

So this commit makes Impostor wait for hosts to actually kill the player
using SetRole. Do set the LastDeathReason property though for players
using the API.