Fixes disposal self deletion (#64612)

Disposal holders are meant to stack up in the pipe if they're not moving
The check for this is typically done using the active variable when two
holders collide.
Unfortunately when I converted holders over to move loops, I forgot to
set active to false properly.

This means the part of deconstruct code that handled ejecting the
contents of the pipe couldn't really function, since there was more then
one holder stored in the pipe. so all but one of the holders just got
qdel'd. Not good, makes people upset for some reason

This resolves that issue

code/modules/recycling/disposal/holder.dm

@@ -89,6 +89,7 @@
 	SIGNAL_HANDLER
 	current_pipe = null
 	last_pipe = null
+	active = FALSE
 
 //failsafe in the case the holder is somehow forcemoved somewhere that's not a disposal pipe. Otherwise the above loop breaks.
 /obj/structure/disposalholder/Moved(atom/oldLoc, dir)