Removed GridSlotState enum.

Author: ChebanovDD

Assets/Plugins/Match3.Tests/EditMode/GameBoardTests.cs

@@ -1,6 +1,5 @@
 using System;
 using Match3.App.Internal;
-using Match3.Core.Enums;
 using Match3.Core.Interfaces;
 using Match3.Core.Structs;
 using NUnit.Framework;

Assets/Plugins/Match3.Tests/EditMode/GridSlotTests.cs

@@ -1,5 +1,4 @@
 using System;
-using Match3.Core.Enums;
 using Match3.Core.Interfaces;
 using Match3.Core.Models;
 using Match3.Core.Structs;