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/modules/mob/mob_helpers.dm

@@ -281,7 +281,7 @@ It's fairly easy to fix if dealing with single letters but not so much with comp
 
 /mob/proc/abiotic(full_body = 0)
 	for(var/obj/item/I in held_items)
-		if(!(I.flags_1 & NODROP_1))
+		if(!(I.flags & NODROP))
 			return 1
 	return 0