Fire Pillar, Acid Bomb fixes
- Fire Pillar can no longer hit plants (follow-up to https://github.com/rathena/rathena/commit/04a1173f7d4c0e1ffbace05d34d8b60dfd037a94)
- Acid Bomb will now hit every 500ms instead of every 1000ms on renewal (related to bugreport:6338)