Commandbook conflicts with Clearlag

CMDBOOK-2436 - Reported by Dats_me

Commandbook 2.4 & 2.5 causes Clearlag -->KeepDeathDrop to stop working.
ClearLag's auto clear and manual clear commands removes players deathdropped items.
Disable Commandbook and it works correctly (does not delete death dropped items).

Versions tested and able to duplicate with:
CommandBook v2.5-SNAPSHOT.1769-eb34539
CommandBook v2.4:1692-75bb1c8,master
ClearLag v2.8.3
KeepDeathDrop v1.0.2

使用 CommandBook 2.4 或 2.5、ClearLag 2.8.3 和 KeepDeathDrop 1.0.2 重现冲突，并比较启用和禁用 CommandBook 时 ClearLag 的自动清理和手动清理。完成的标准是 ClearLag 不再移除玩家死亡时掉落的物品。

由索引模型根据 Issue 内容生成。