Don't use Environment.Exit (#20532)

* [Awake] Don't use Process.Exit and move to CsWin32

* [PowerLauncher] Remove unused API

* [ColorPicker] Use cancellable NativeEventWaiter + cleanup using

* [TextExtractor] Don't use Environment.Exit

* [MeasureTool] Don't use Environment.Exit(0);

* [FZE] don't use Environment.Exit and fix WaitForPowerToysRunner

src/common/Common.UI/CustomLibraryThemeProvider.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections.Generic;
+
 using ControlzEx.Theming;
 
 namespace Common.UI

src/common/Common.UI/NativeEventWaiter.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Threading;
+
+using Dispatcher = System.Windows.Threading.Dispatcher;
+
+namespace Common.UI
+{
+    public static class NativeEventWaiter
+    {
+        public static void WaitForEventLoop(string eventName, Action callback, Dispatcher dispatcher, CancellationToken cancel)
+        {
+            new Thread(() =>
+            {
+                var eventHandle = new EventWaitHandle(false, EventResetMode.ManualReset, eventName);
+                while (true)
+                {
+                    if (WaitHandle.WaitAny(new WaitHandle[] { cancel.WaitHandle, eventHandle }) == 1)
+                    {
+                        dispatcher.BeginInvoke(callback);
+                    }
+                    else
+                    {
+                        return;
+                    }
+                }
+            }).Start();
+        }
+    }
+}