Actors that use types from a level that got unloaded should now get
killed immediately instead of continuing to exist and eventually crash
the game.
NOTE: Will spam the console whenever a bad actor tries to spawn. I would
like to document all instances of where this happens!
Mostly easy / particle def files. I did a bit in `ruins` but CFG
failures and missing `drawable` functions make it untestable for now so
I've put that on pause.
