update: 优化回调接口

Runtime/GuruCore/Runtime/Common/GuruSDKCallback.cs

@@ -40,16 +40,6 @@ namespace Guru
             return ins;
         }
         
-        private void SubCallback(Action<string> callback)
-        {
-            msgCallback -= callback;
-        }
-        
-        private void SubCallback(Action<string> callback)
-        {
-            msgCallback -= callback;
-        }
-        
         /// <summary>
         /// External 回调参数
         /// </summary>
@@ -77,14 +67,5 @@ namespace Guru
             Instance.msgCallback -= callback;
         }
         
-        /// <summary>
-        /// 添加回调
-        /// </summary>
-        /// <param name="callback"></param>
-        public static void RemoveCallback(Action<string> callback)
-        {
-            Instance.SubCallback(callback);
-        }
-
     }
 }