managed_overlays no longer stores as a list for singletons (#60320)
managed_overlays no longer stores as a list for singletons (#60320)

This is kinda on the snowflakely side, but im ok with the concept for cases like this. Nearly every movable with smoothing only has a single item list containing the smoothing overlay, this includes pipes, wires, windows, tables, lattices, etc.  This seems like a large enough waste to justify the type confusion between lists and an appearance.
coiax/-tg-station,MicroWorldwide/SS13-TG-station,MicroWorldwide/SS13-TG-station,MicroWorldwide/SS13-TG-station,Bawhoppen/-tg-station,WJohn/-tg-station,Bawhoppen/-tg-station,coiax/-tg-station,WJohn/-tg-station,ShizCalev/tgstation,Cruix/-tg-station,MicroWorldwide/SS13-TG-station,CPTANT/-tg-station,Jordie0608/tgstation,MicroWorldwide/SS13-TG-station,Jordie0608/tgstation,MicroWorldwide/SS13-TG-station,Cruix/-tg-station,WJohn/-tg-station,CPTANT/-tg-station,Cruix/-tg-station,Jordie0608/tgstation,tgstation/tgstation,WJohn/-tg-station,MicroWorldwide/SS13-TG-station,coiax/-tg-station,Jordie0608/tgstation,Bawhoppen/-tg-station,Cruix/-tg-station,Cruix/-tg-station,CPTANT/-tg-station,coiax/-tg-station,Bawhoppen/-tg-station,Razharas/-tg-station,MicroWorldwide/SS13-TG-station,tgstation/tgstation,tgstation/tgstation,ShizCalev/tgstation,Razharas/-tg-station,ShizCalev/tgstation,Jordie0608/tgstation,Jordie0608/tgstation,CPTANT/-tg-station,tgstation/tgstation,Razharas/-tg-station,ShizCalev/tgstation,tgstation/tgstation,tgstation/-tg-station,Bawhoppen/-tg-station,ShizCalev/tgstation,ShizCalev/tgstation,Jordie0608/tgstation,Cruix/-tg-station,tgstation/-tg-station,CPTANT/-tg-station,CPTANT/-tg-station,tgstation/-tg-station,Cruix/-tg-station,Bawhoppen/-tg-station,Jordie0608/tgstation,WJohn/-tg-station,CPTANT/-tg-station,Razharas/-tg-station,Razharas/-tg-station,coiax/-tg-station,Bawhoppen/-tg-station,coiax/-tg-station,tgstation/tgstation,Cruix/-tg-station,ShizCalev/tgstation,tgstation/tgstation,tgstation/-tg-station,WJohn/-tg-station,Bawhoppen/-tg-station,Razharas/-tg-station,tgstation/tgstation,CPTANT/-tg-station,coiax/-tg-station,WJohn/-tg-station,ShizCalev/tgstation,Razharas/-tg-station,Razharas/-tg-station