Default: Remove 'player falling damage' sound

This plays when damage is disabled, an engine bug.
We can remove it because both sounds are identical, now it is removed
the 'player damage' sound still plays when falling damage is taken.

mods/default/README.txt

@@ -197,7 +197,6 @@ Glass breaking sounds (CC BY 3.0):
 sonictechtonic (CC BY 3.0):
 https://www.freesound.org/people/sonictechtonic/sounds/241872/
   player_damage.ogg
-  player_falling_damage.ogg
 
 Mito551 (sounds) (CC BY-SA 3.0):
   default_dig_choppy.ogg