Remove DROPS_AMMO from firefighter bot

Liquid-loaded robots drop bottled liquids when they drop ammo on-death. As the liquid should drop on the ground but doesn't, dropping the flag fixes obvious problems

data/mods/Salvaged_Robots/monsters.json

@@ -377,7 +377,7 @@
         "ranges": [ [ 0, 5, "BURST" ] ]
       }
     ],
-    "extend": { "flags": [ "FIREPROOF", "BASHES", "DROPS_AMMO" ] }
+    "extend": { "flags": [ "FIREPROOF", "BASHES" ] }
   },
   {
     "id": "mon_utilibot_blob",