paintings now drop canvas and frame when knocked off the wall (#85894)

## About The Pull Request
Also, this PR polishes the clown frame. The honkin' red nose looked
pretty malformed.

## Why It's Good For The Game
Fixing a few issues with paintings. 

## Changelog

🆑
fix: paintings now drop canvas and frame when knocked off the wall.
/🆑

code/modules/art/paintings.dm

@@ -559,6 +559,8 @@
 		/obj/item/canvas/twentythree_twentythree,
 		/obj/item/canvas/twentyfour_twentyfour,
 	)
+	/// the type of wallframe it 'disassembles' into
+	var/wallframe_type = /obj/item/wallframe/painting
 
 WALL_MOUNT_DIRECTIONAL_HELPERS(/obj/structure/sign/painting)
 
@@ -579,6 +581,16 @@ WALL_MOUNT_DIRECTIONAL_HELPERS(/obj/structure/sign/painting)
 	else
 		return ..()
 
+/obj/structure/sign/painting/knock_down(mob/living/user)
+	var/turf/drop_turf
+	if(user)
+		drop_turf = get_turf(user)
+	else
+		drop_turf = drop_location()
+	current_canvas?.forceMove(drop_turf)
+	var/obj/item/wallframe/frame = new wallframe_type(drop_turf)
+	frame.update_integrity(get_integrity()) //Transfer how damaged it is.
+
 /obj/structure/sign/painting/examine(mob/user)
 	. = ..()
 	if(persistence_id)
@@ -784,6 +796,7 @@ WALL_MOUNT_DIRECTIONAL_HELPERS(/obj/structure/sign/painting)
 		/obj/item/canvas/thirtysix_twentyfour,
 		/obj/item/canvas/fortyfive_twentyseven,
 	)
+	wallframe_type = /obj/item/wallframe/painting/large
 
 /obj/structure/sign/painting/large/Initialize(mapload)
 	. = ..()