Broken bones now hurt less on rollerbeds (#3024)

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## About The Pull Request

fixes #2968

splints would work for some stuff but they are both uncommon (only spawn
in like brute kits/need to be crafted) and don't work on the head or
chest. Also gives rollerbeds a niche

## Why It's Good For The Game

Life or random damage ticks for broken cat

it's a bit unintuitive that putting someone on a rollerbed won't make
them resistant/immune to bone jostling

## Changelog

:cl:
balance: Rollerbeds stop broken bone damage ticks from occurring while
buckled
/:cl:

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---------

Signed-off-by: Theos <[email protected]>

code/modules/surgery/bodyparts/bodyparts.dm

@@ -745,8 +745,8 @@
 	bone_status = BONE_FLAG_NORMAL
 
 /obj/item/bodypart/proc/on_mob_move()
-	// Dont trigger if it isn't broken or if it has no owner
-	if(bone_status != BONE_FLAG_BROKEN || !owner)
+	// Dont trigger if it isn't broken or if it has no owner or is buckled to a rollerbed
+	if(bone_status != BONE_FLAG_BROKEN || !owner || istype(owner?.buckled, /obj/structure/bed/roller))
 		return
 
 	if(prob(5))