refactor: remove unused using command

Author: Misaka-L

src/Packages/com.yuxiaviation.v320neo.fdmi/Runtime/Avionics/Instruments/Clock/Clock.cs

@@ -1,6 +1,5 @@
 using System;
 using JetBrains.Annotations;
-using tech.gyoku.FDMi.core;
 using TMPro;
 using UdonSharp;
 using UnityEngine;