Fixed self reference loop (#1190)

Fixed NullReferenceException

Author: tsvietOK

Files/DataModels/SidebarPinnedModel.cs

@@ -12,6 +12,7 @@ namespace Files.DataModels
 {
     public class SidebarPinnedModel
     {
+        [JsonIgnore]
         public SettingsViewModel AppSettings => App.AppSettings;
 
         public static readonly string JsonFileName = "PinnedItems.json";

Files/Views/InstanceTabsView.xaml.cs

@@ -38,8 +38,8 @@ public InstanceTabsView()
             CoreTitleBar.ExtendViewIntoTitleBar = true;
             tabView = TabStrip;
 
-            App.SidebarPinned = new SidebarPinnedModel();
             App.AppSettings = new SettingsViewModel();
+            App.SidebarPinned = new SidebarPinnedModel();
             App.InteractionViewModel = new InteractionViewModel();
 
             // Turn on Navigation Cache