Lights now call update when moving Z-levels. (#96934)

## About The Pull Request

As it says on the tin, light fixtures now call update when their Z-level
changes. The intention here is to help fix lighting issues on shuttles,
primarily the cargo shuttle and escape shuttle, to keep the shuttle(s)
from arriving pitch black unless the bulb is replaced.

## Why It's Good For The Game

This bug has been frusterating me for a bit. That said, I'm not 100%
confident that this change is going to consistently or completely solve
the issue, but does provide an additional way for lighting to fix
itself, potentially.

## Changelog

🆑
fix: Lights will now update themselves when moving Z-levels.
/🆑

code/modules/power/lighting/light.dm

@@ -750,6 +750,11 @@
 			continue
 		INVOKE_ASYNC(src, PROC_REF(flicker))
 
+/obj/machinery/light/on_changed_z_level(turf/old_turf, turf/new_turf, same_z_layer, notify_contents)
+	. = ..()
+	if(!QDELING(src))
+		update(FALSE)
+
 /obj/machinery/light/floor
 	name = "floor light"
 	desc = "A lightbulb you can walk on without breaking it, amazing."