Rebalance of MO_ABSORBSPIRITS (Absorb Spirit Sphere)

- Reduced fixed casting time: 1s -> 0.5s
- Removed variable casting time

From massive skills rebalance (1st/2nd/transclass) (2018.10.31)

Author: guilherme-gm

db/re/skill_db.conf

@@ -7979,8 +7979,7 @@ skill_db: (
 		NoDamage: true
 	}
 	InterruptCast: true
-	CastTime: 1000
-	FixedCastTime: 1000
+	FixedCastTime: 500
 	Requirements: {
 		SPCost: 5
 	}