Fixes layering issues brought by the FoV PR. (#63903)

* Fixed most (not all) incorrect planes and layers detected by the unit test.

code/game/objects/structures/fluff.dm

@@ -79,6 +79,7 @@
 	density = TRUE
 	deconstructible = FALSE
 	layer = EDGED_TURF_LAYER
+	plane = GAME_PLANE_UPPER
 /**
  * A variety of statue in disrepair; parts are broken off and a gemstone is missing
  */
@@ -104,6 +105,7 @@
 	icon_state = "frontwalltop"
 	density = FALSE
 	layer = ABOVE_ALL_MOB_LAYER //except for the stairs tile, which should be set to OBJ_LAYER aka 3.
+	plane = ABOVE_GAME_PLANE
 
 
 /obj/structure/fluff/bus/passable/seat
@@ -112,6 +114,7 @@
 	icon_state = "backseat"
 	pixel_y = 17
 	layer = OBJ_LAYER
+	plane = GAME_PLANE
 
 
 /obj/structure/fluff/bus/passable/seat/driver