Don't crash if close window when picking data dir

StabilityMatrix/App.xaml.cs

@@ -345,7 +345,12 @@ namespace StabilityMatrix
         private void App_OnExit(object sender, ExitEventArgs e)
         {
             serviceProvider?.GetRequiredService<LaunchViewModel>().OnShutdown();
-            serviceProvider?.GetRequiredService<ILiteDbContext>().Dispose();
+            var settingsManager = serviceProvider?.GetRequiredService<ISettingsManager>();
+
+            if (settingsManager?.TryFindLibrary() ?? false)
+            {
+                serviceProvider?.GetRequiredService<ILiteDbContext>().Dispose();
+            }
         }
 
         [DoesNotReturn]

StabilityMatrix/MainWindow.xaml.cs

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