Revert "[MIRROR] Replace all secondary flags with bitflags stored in the flags_2 var" (#2457)

ok you know what yeah i think i'll properly mirror https://github.com/Citadel-Station-13/Citadel-Station-13/pull/2411

code/game/objects/items/stacks/tiles/light.dm

@@ -3,7 +3,7 @@
 	singular_name = "light floor tile"
 	desc = "A floor tile, made out of glass. It produces light."
 	icon_state = "tile_e"
-	flags_1 = CONDUCT_1
+	flags = CONDUCT
 	attack_verb = list("bashed", "battered", "bludgeoned", "thrashed", "smashed")
 	turf_type = /turf/open/floor/light
 	var/state = 0

code/game/objects/items/stacks/tiles/tile_types.dm

@@ -211,7 +211,7 @@
 	force = 6
 	materials = list(MAT_METAL=500)
 	throwforce = 10
-	flags_1 = CONDUCT_1
+	flags = CONDUCT
 	turf_type = /turf/open/floor/plasteel
 	mineralType = "metal"
 	armor = list(melee = 0, bullet = 0, laser = 0, energy = 0, bomb = 0, bio = 0, rad = 0, fire = 100, acid = 70)