Fix: Infinite Carbon Copies (#3866)

# About the pull request
Infinite paper is fun until you start to set fire to it.
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# Explain why it's good for the game
Bugsssssssss (well, more of an oversight)
# Testing Photographs and Procedure
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# Changelog
:cl:
fix: Carbon copies can no longer infinitely breed.
/:cl:

code/modules/paperwork/carbonpaper.dm

@@ -30,7 +30,7 @@
 	set category = "Object"
 	set src in usr
 
-	if (copied == 0)
+	if (!copied && !iscopy)
 		var/obj/item/paper/carbon/c = src
 		var/copycontents = html_decode(c.info)
 		var/obj/item/paper/carbon/copy = new /obj/item/paper/carbon (usr.loc)