Don't crash if close window when picking data dir

StabilityMatrix/App.xaml.cs

@@ -345,8 +345,13 @@ namespace StabilityMatrix
         private void App_OnExit(object sender, ExitEventArgs e)
         {
             serviceProvider?.GetRequiredService<LaunchViewModel>().OnShutdown();
+            var settingsManager = serviceProvider?.GetRequiredService<ISettingsManager>();
+
+            if (settingsManager?.TryFindLibrary() ?? false)
+            {
                 serviceProvider?.GetRequiredService<ILiteDbContext>().Dispose();
             }
+        }
 
         [DoesNotReturn]
         private void App_DispatcherUnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)

StabilityMatrix/MainWindow.xaml.cs

@@ -127,7 +127,11 @@ namespace StabilityMatrix
         {
             var interopHelper = new WindowInteropHelper(this);
             var placement = ScreenExtensions.GetPlacement(interopHelper.Handle);
+
+            if (settingsManager.TryFindLibrary())
+            {
                 settingsManager.SetPlacement(placement.ToString());
             }
         }
+    }
 }