Fix Design Disks (shiptest-ss13#3622)

## About The Pull Request

Design disks work again

## Why It's Good For The Game

This is probably going to die before Christmas but we should have
features that work

## Changelog

:cl:
fix: Design disks work again
/:cl:

code/modules/research/rdconsole.dm

@@ -633,10 +633,10 @@ Nothing else in the console has ID requirements.
 	RDSCREEN_UI_DDISK_CHECK
 	var/list/l = list()
 	l += "Disk Operations: <A href='?src=[REF(src)];clear_design=0'>Clear Disk</A><A href='?src=[REF(src)];updt_design=0'>Upload All</A><A href='?src=[REF(src)];eject_design=1'>Eject Disk</A>"
-	for(var/i in 1 to d_disk.max_blueprints)
+	for(var/i in d_disk.blueprints)
 		l += "<div class='statusDisplay'>"
-		if(d_disk.blueprints[i])
-			var/datum/design/D = d_disk.blueprints[i]
+		if(istype(i, /datum/design))
+			var/datum/design/D = i
 			l += "[D.icon_html(usr)] <A href='?src=[REF(src)];view_design=[D.id]'>[D.name]</A>"
 			l += "Operations: <A href='?src=[REF(src)];updt_design=[i]'>Upload to database</A> <A href='?src=[REF(src)];clear_design=[i]'>Clear Slot</A>"
 		else