Fixes propaganda posters in CL office (#4930)

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# About the pull request

Fixes #4916 

It looks like someone wanted this to be the IO poster but didn't quite
get there.

# Explain why it's good for the game

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# Testing Photographs and Procedure
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<summary>Screenshots & Videos</summary>

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:cl:
fix: Fixes posters in CL office displaying IO description.
/:cl:

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code/game/objects/effects/decals/posters.dm

@@ -184,6 +184,12 @@
 	serial_number = pick(27,28,30,31)
 	.=..()
 
+/obj/structure/sign/poster/io
+	icon_state = "poster14"
+
+/obj/structure/sign/poster/io/Initialize()
+	serial_number = 14
+	. = ..()
 ////////////////
 //Hero Posters//
 ////////////////

maps/map_files/USS_Almayer/USS_Almayer.dmm

@@ -36331,11 +36331,9 @@
 /obj/structure/flora/pottedplant{
 	icon_state = "pottedplant_21"
 	},
-/obj/structure/sign/poster{
-	desc = "A large piece of cheap printed paper. This one proudly demands that you REMEMBER IO!";
-	icon_state = "poster14";
-	name = "propaganda poster";
-	pixel_y = 32
+/obj/structure/sign/poster/io{
+	pixel_y = 32;
+	name = "propaganda poster"
 	},
 /obj/structure/sign/safety/escapepod{
 	pixel_x = -17
@@ -39271,11 +39269,9 @@
 /obj/structure/machinery/photocopier{
 	anchored = 0
 	},
-/obj/structure/sign/poster{
-	desc = "A large piece of cheap printed paper. This one proudly demands that you REMEMBER IO!";
-	icon_state = "poster14";
-	name = "propaganda poster";
-	pixel_y = 32
+/obj/structure/sign/poster/io{
+	pixel_y = 32;
+	name = "propaganda poster"
 	},
 /turf/open/floor/wood/ship,
 /area/almayer/command/corporateliason)