Chutes no longer play sounds on top of each other. Pipe ejections are…

… a bit quieter too (tgstation#83470)

## About The Pull Request

Chutes were playing a sound per item in a stack because the condition
was that the last played sound happened before worldtime+1 which was
always the case, that's in the future. They now only play a single sound
when multiple items enter them at once.
Outlets functioned correctly but the sound for midpipe ejections was a
bit overpowering, so I deadened it a bit(-4 LUFS).
Tested. No observed effect on consecutive insertions.

## Why It's Good For The Game

It is often the case that a conveyor with a large stack of items may be
activated, pushing a large quantity of items into a chute, which would
then fry the eardrums of all those nearby.

## Changelog

:cl:
sound: Disposal chutes will no longer play a sound for each item when
many items enter it at once
/:cl:

code/modules/recycling/disposal/bin.dm

@@ -241,7 +241,7 @@
  flushing = TRUE
  flushAnimation()
  sleep(1 SECONDS)
- if(last_sound < world.time + 1)
+ if(last_sound < world.time - 1) //Prevents piles of items from playing a dozen sounds at once
  playsound(src, 'sound/machines/disposalflush.ogg', 50, FALSE, FALSE)
  last_sound = world.time
  sleep(0.5 SECONDS)