Get window chrome maximize button by index.

The real Windows Maximize button has no automation ID and is localized. Get it by index instead of by name. The Avalonia one isn't localized so we can get it by name.

tests/Avalonia.IntegrationTests.Appium/WindowTests.cs

@@ -1,18 +1,14 @@
 using System;
-using System.IO;
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading;
 using Avalonia.Controls;
-using Avalonia.Utilities;
-using Avalonia.Media.Imaging;
 using OpenQA.Selenium;
 using OpenQA.Selenium.Appium;
 using OpenQA.Selenium.Interactions;
 using SixLabors.ImageSharp.PixelFormats;
 using Xunit;
 using Xunit.Sdk;
-using OpenQA.Selenium.Appium.Interfaces;
 
 namespace Avalonia.IntegrationTests.Appium
 {
@@ -266,7 +262,9 @@ namespace Avalonia.IntegrationTests.Appium
 
                 if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                 {
-                    maximizeButton = secondaryWindow.FindElementByXPath("//Button[@Name='Maximise']");
+                    maximizeButton = extendClientArea ?
+                        secondaryWindow.FindElementByXPath("//Button[@Name='Maximise']") :
+                        secondaryWindow.FindElementByXPath("//TitleBar/Button[2]");
                 }
                 else
                 {