Minor Gem check optimazation (#5401)

Since the variable is only used once I removed it and replaced it with a direct call. Also the if statement is short enough to fit into one line.

very ocd induced change but I couldn't look away.

src/battle_main.c

@@ -6010,9 +6010,7 @@ void SetTypeBeforeUsingMove(u32 move, u32 battler)
         gBattleStruct->dynamicMoveType = TYPE_ELECTRIC | F_DYNAMIC_TYPE_SET;
 
     // Check if a gem should activate.
-    moveType = GetMoveType(move);
-    if (holdEffect == HOLD_EFFECT_GEMS
-        && moveType == ItemId_GetSecondaryId(heldItem))
+    if (holdEffect == HOLD_EFFECT_GEMS && GetMoveType(move) == ItemId_GetSecondaryId(heldItem))
     {
         gSpecialStatuses[battler].gemParam = GetBattlerHoldEffectParam(battler);
         gSpecialStatuses[battler].gemBoost = TRUE;