Fixing tesla with no balls (#5988)

This PR fixes Tesla not having miniballs. Problem was that it would delete its own generated balls. Fixes #5749

Tesla that has 9 or more balls will start to melt down any tesla coils or grounding rods.

Tesla that has 10 or more balls will start to target and melt down emitters

Tesla with no balls looses power as intended, thus dying with less than 0 power.

code/game/objects/objs.dm

@@ -174,7 +174,12 @@
 /obj/proc/see_emote(mob/M as mob, text, var/emote_type)
 	return
 
-/obj/proc/tesla_act(var/power)
+/obj/proc/tesla_act(var/power, var/melt = FALSE)
+	if(melt)
+		visible_message(span("danger", "\The [src] melts down until ashes are left!"))
+		new /obj/effect/decal/cleanable/ash(loc)
+		qdel(src)
+		return
 	being_shocked = 1
 	var/power_bounced = power / 2
 	tesla_zap(src, 3, power_bounced)