修复首选项文件不存在时的提示信息

SpineViewer/Utils/JsonHelper.cs

@@ -40,13 +40,16 @@ namespace SpineViewer.Utils
         /// <summary>
         /// 从文件反序列对象, 不会抛出异常
         /// </summary>
-        public static bool Deserialize<T>(string path, out T obj)
+        public static bool Deserialize<T>(string path, out T obj, bool quietForNotExist = false)
         {
             if (!File.Exists(path))
+            {
+                if (!quietForNotExist)
                 {
                     _logger.Error("Json file {0} not found", path);
                     MessagePopupService.Error($"Json file {path} not found");
                 }
+            }
             else
             {
                 try

SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs

@@ -63,7 +63,7 @@ namespace SpineViewer.ViewModels.MainWindow
         /// </summary>
         public void LoadPreference()
         {
-            if (JsonHelper.Deserialize<PreferenceModel>(PreferenceFilePath, out var obj)) 
+            if (JsonHelper.Deserialize<PreferenceModel>(PreferenceFilePath, out var obj, true)) 
                 Preference = obj;
         }