[MIRROR] Boss music stops on mob death [MDB IGNORE] (#22896)

* Boss music stops on mob death (#77335)

## About The Pull Request

Listens for the death of people fighting w/ boss music and kicks them
out early if they die, which stops the music from playing to them.

## Why It's Good For The Game

You won't have to listen to boss music of something that just killed
you.

## Changelog

🆑
fix: Boss music cuts out when you die.
/🆑

* Boss music stops on mob death

---------

Co-authored-by: John Willard <53777086+JohnFulpWillard@users.noreply.github.com>

code/datums/components/boss_music.dm

@@ -52,9 +52,16 @@
 		return
 
 	players_listening_refs += new_ref
+	RegisterSignal(new_target, COMSIG_LIVING_DEATH, PROC_REF(on_mob_death))
 	music_callbacks += addtimer(CALLBACK(src, PROC_REF(clear_target), new_ref), track_duration, TIMER_STOPPABLE)
 	new_target.playsound_local(new_target, boss_track, 200, FALSE, channel = CHANNEL_BOSS_MUSIC, pressure_affected = FALSE, use_reverb = FALSE)
 
+///Called when a mob listening to boss music dies- ends their music early.
+/datum/component/boss_music/proc/on_mob_death(mob/living/source)
+	SIGNAL_HANDLER
+	var/datum/weakref/player_ref = WEAKREF(source)
+	clear_target(player_ref)
+
 ///Removes `old_target` from the list of players listening, and stops their music if it is still playing.
 ///This allows them to have music played again if they re-enter combat with this fauna.
 /datum/component/boss_music/proc/clear_target(datum/weakref/old_ref)
@@ -62,4 +69,5 @@
 
 	var/mob/old_target = old_ref?.resolve()
 	if(old_target)
+		UnregisterSignal(old_target, COMSIG_LIVING_DEATH)
 		old_target.stop_sound_channel(CHANNEL_BOSS_MUSIC)