fix namepsace

Author: jcs090218

Assets/JCSUnity/Scripts/UI/Dropdown/JCS_DropdownScreenResolution.cs

@@ -1,9 +1,7 @@
-using System.Collections.Generic;
+using System.Linq;
 using UnityEngine;
 using TMPro;
 using MyBox;
-using System.Linq;
-
 
 #if UNITY_EDITOR
 using UnityEditor;