Fix `IfAttribute` using property

[DarkRewar]

using BaseTool;
using UnityEngine;

public class Test : MonoBehaviour
{
  public enum MyEnum 
  {
    TwoD,
    ThreeD
  }
  
  [SerializeField] private MyEnum _dimension = MyEnum.ThreeD;
  public bool Is2D => _dimension == MyEnum.TwoD;

  [If(nameof(Is2D))]
  public GameObject Prefab2D;
}