Revert "Stairs are Dangerous" (#19484)

Unfortunately most of the map is kind of unplayable or not mapped in
mind with stairs being untraversable for roller beds or wheelchairs.
Remapping every map to work with this mechanic is also not something I
am interested in.

---------

Co-authored-by: Matt Atlas <liermattia@gmail.com>

code/game/objects/items/bodybag.dm

@@ -142,9 +142,6 @@
 /obj/structure/closet/body_bag/animate_door()
 	flick("[initial(icon_state)]_anim_[opened ? "open" : "close"]", src)
 
-/obj/structure/closet/body_bag/stair_act() //Stops body bags flying open when pulled down stairs
-	return
-
 /obj/item/bodybag/cryobag
 	name = "stasis bag"
 	desc = "A folded, reusable bag designed to prevent additional damage to an occupant, especially useful if short on time or in \

code/game/objects/objs.dm

@@ -301,7 +301,3 @@
 /obj/proc/clean()
 	clean_blood()
 	color = initial(color)
-
-/// This fires when the object /crosses() a stair object
-/obj/proc/stair_act()
-	return

code/game/objects/structures/crates_lockers/closets.dm

@@ -802,19 +802,6 @@
 	new /obj/item/stack/material/steel(get_turf(src))
 	qdel(src)
 
-/obj/structure/closet/stair_act()
-	if(opened || !can_open())
-		return
-
-	visible_message(SPAN_WARNING("\The [src] flies open as it bounces on the stairs!"))
-	for(var/thing in src)
-		var/atom/movable/AM = thing
-		AM.forceMove(get_turf(src))
-		AM.throw_at_random(TRUE, 1, 2)
-	open()
-
-	return ..()
-
 /*
 ==========================
 	Contents Scanner

code/game/objects/structures/stool_bed_chair_nest/bed.dm

@@ -306,21 +306,6 @@
 		else
 			occupant.visible_message(SPAN_DANGER("[occupant] crashed into \the [A]!"))
 
-/obj/structure/bed/stair_act()
-	if(!buckled)
-		return
-
-	var/atom/movable/unbuckled_atom = unbuckle()
-	if(!unbuckled_atom)
-		return
-
-	unbuckled_atom.visible_message("<b>\The [unbuckled_atom]</b> goes flying out of \the [src] as it bounces on the stairs!", SPAN_WARNING("You go flying out of \the [src] as it bounces on the stairs!"))
-	unbuckled_atom.throw_at_random(FALSE, 1, 2)
-
-	if(ismob(unbuckled_atom))
-		var/mob/unbuckled_mob = unbuckled_atom
-		unbuckled_mob.Paralyse(5)
-
 /obj/structure/bed/psych
 	name = "psychiatrist's couch"
 	desc = "For prime comfort during psychiatric evaluations."
@@ -578,9 +563,6 @@
 	.=..()
 	set_light(2,1,LIGHT_COLOR_CYAN)
 
-/obj/structure/bed/roller/hover/stair_act()
-	return
-
 /obj/item/roller
 	name = "roller bed"
 	desc = "A collapsed roller bed that can be carried around."