Fixes flashdark (#85454)

## About The Pull Request

Flashdarks now actually produce darkness. The bugfix that broke this
added their fix to them even though the bug didnt apply here. (#79240)

![image](https://github.com/user-attachments/assets/5c23ac5d-ce73-4b40-92c9-2c7c2770730b)

closes https://github.com/tgstation/tgstation/issues/68638

## Why It's Good For The Game

A bugfix is good for the game.

## Changelog

🆑
fix: Flashdarks now broduce darkness upon toggling
/🆑

code/game/objects/items/devices/flashlight.dm

@@ -963,14 +963,10 @@
 	var/dark_light_range = 2.5
 	///Variable to preserve old lighting behavior in flashlights, to handle darkness.
 	var/dark_light_power = -3
-	var/on = FALSE
 
 /obj/item/flashlight/flashdark/update_brightness()
 	. = ..()
-	if(on)
-		set_light(dark_light_range, dark_light_power)
-	else
-		set_light(0)
+	set_light(dark_light_range, dark_light_power)
 
 //type and subtypes spawned and used to give some eyes lights,
 /obj/item/flashlight/eyelight