Adds some nodiagonal walls to the luxury shuttle (#72659)

## About The Pull Request

Something always felt a little bit off about this shuttle, but I never
noticed anything wrong until I looked at it as an observer.


![image](https://user-images.githubusercontent.com/28870487/211973033-d6d00ae2-0465-468f-bb9d-04117cba49a3.png)


![image](https://user-images.githubusercontent.com/28870487/211973016-c0779ff4-d2a1-41a8-819c-ab47bde95447.png)

Yeah that definitely ain't right.
## Why It's Good For The Game

It's the LUXURY shuttle. It should look nice!
## Changelog
🆑
fix: The walls of the luxury shuttle no longer bend in strange
directions.
/🆑

_maps/shuttles/emergency_luxury.dmm

@@ -888,6 +888,9 @@
 /obj/machinery/light/directional/west,
 /turf/open/floor/mineral/titanium/white,
 /area/shuttle/escape/luxury)
+"xz" = (
+/turf/closed/indestructible/riveted/plastinum/nodiagonal,
+/area/shuttle/escape/luxury)
 "zh" = (
 /turf/open/floor/mineral/diamond,
 /area/shuttle/escape/luxury)
@@ -1054,7 +1057,7 @@ ag
 ag
 af
 ag
-ag
+xz
 ay
 av
 av
@@ -1118,7 +1121,7 @@ ag
 Lt
 ag
 ag
-ag
+xz
 bV
 aC
 aE
@@ -1203,7 +1206,7 @@ bW
 bY
 ao
 ci
-ag
+xz
 ag
 ag
 bb
@@ -1311,7 +1314,7 @@ bc
 bc
 bc
 bc
-ag
+xz
 ag
 ag
 ag