You can't use null as a grouped status effect source (#93782)

## About The Pull Request

Fixes https://github.com/tgstation/tgstation/issues/88311

1. Grouped status effects will throw a stack trace if trying to pass
null as a source
2. Fishing hooks will not proceed to hook if they fail to hook (lol)
3. Replaced cursed slot machine "grouped effect" with a normal effect
(since it didn't use the group aspect at all)

## Changelog

🆑 Melbert
fix: Fishing hooks will no longer hook even though the hook failed
/🆑

code/modules/mapfluff/ruins/objects_and_mobs/cursed_slot_machine.dm

@@ -80,8 +80,8 @@
 	COOLDOWN_START(src, spin_cooldown, cooldown_length)
 
 	if(!prob(win_prob))
-		if(status_effect_on_roll && isnull(user.has_status_effect(/datum/status_effect/grouped/cursed)))
-			user.apply_status_effect(/datum/status_effect/grouped/cursed)
+		if(status_effect_on_roll)
+			user.apply_status_effect(/datum/status_effect/slot_machine_curse)
 
 		SEND_SIGNAL(user, COMSIG_CURSED_SLOT_MACHINE_LOST)
 		playsound(src, 'sound/machines/buzz/buzz-sigh.ogg', 30, TRUE)