PowerToys Run cache issue (#4472)

* Clean termination of powertoys process.

* Fixed issue with run not responding to WM_CLOSE

* Fixed serialization error in pinyin and image cache

* Fixed merge conflict

* Fixed nit wrt to master

* Fixed undeterministic behaviour of Environment.Exit function

* Update timing for terminate process

src/modules/fancyzones/editor/FancyZonesEditor/App.xaml.cs

@@ -25,7 +25,9 @@ namespace FancyZonesEditor
 
         private void OnStartup(object sender, StartupEventArgs e)
         {
-            RunnerHelper.WaitForPowerToysRunner(Settings.PowerToysPID);
+            RunnerHelper.WaitForPowerToysRunner(Settings.PowerToysPID, () => {
+                Environment.Exit(0);
+            });
 
             LayoutModel foundModel = null;