Runtime fix for Telecomms machines, hopefully
Runtime in question:
The following runtime has occured 17 time(s).
runtime error: Cannot read null.name
proc name: Topic (/obj/machinery/telecomms/Topic)
  source file: machine_interactions.dm,346
  usr: M.I.N.D. (/mob/living/silicon/ai)
  src: Bus Mainframe (/obj/machinery/telecomms/bus/preset_three)