stops people from buckling others when they shouldn't be able to (#6807)

# About the pull request

adds checks to stop people from buckling others when they are knocked
out etc.

# Explain why it's good for the game

fixes bug


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

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
fix: stops people from buckling others when they are knocked out etc.
/:cl:

code/game/objects/objs.dm

@@ -277,7 +277,11 @@
 
 //trying to buckle a mob
 /obj/proc/buckle_mob(mob/M, mob/user)
-	if (!ismob(M) || (get_dist(src, user) > 1) || user.is_mob_restrained() || user.stat || buckled_mob || M.buckled || !isturf(user.loc))
+	if (!ismob(M) || (get_dist(src, user) > 1) || user.stat || buckled_mob || M.buckled || !isturf(user.loc))
+		return
+
+	if (user.is_mob_incapacitated() || HAS_TRAIT(user, TRAIT_IMMOBILIZED) || HAS_TRAIT(user, TRAIT_FLOORED))
+		to_chat(user, SPAN_WARNING("You can't do this right now."))
 		return
 
 	if (isxeno(user) && !HAS_TRAIT(user, TRAIT_OPPOSABLE_THUMBS))
@@ -286,11 +290,6 @@
 	if (iszombie(user))
 		return
 
-	// mobs that become immobilized should not be able to buckle themselves.
-	if(M == user && HAS_TRAIT(user, TRAIT_IMMOBILIZED))
-		to_chat(user, SPAN_WARNING("You are unable to do this in your current state."))
-		return
-
 	if(density)
 		density = FALSE
 		if(!step(M, get_dir(M, src)) && loc != M.loc)