Disable focus test on mac.

Because I can't work out how to implement the extremely advanced use-case of finding out whether a control is focused there /s

tests/Avalonia.IntegrationTests.Appium/ElementExtensions.cs

@@ -31,8 +31,16 @@ namespace Avalonia.IntegrationTests.Appium
 
         public static bool GetIsFocused(this AppiumWebElement element)
         {
-            var active = element.WrappedDriver.SwitchTo().ActiveElement() as AppiumWebElement;
-            return element.Id == active?.Id;
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                var active = element.WrappedDriver.SwitchTo().ActiveElement() as AppiumWebElement;
+                return element.Id == active?.Id;
+            }
+            else
+            {
+                // https://stackoverflow.com/questions/71807788/check-if-element-is-focused-in-appium
+                throw new NotSupportedException("Couldn't work out how to check if an element is focused on mac.");
+            }
         }
 
         public static void SendClick(this AppiumWebElement element)

tests/Avalonia.IntegrationTests.Appium/MenuTests.cs

@@ -145,7 +145,7 @@ namespace Avalonia.IntegrationTests.Appium
             Assert.Equal("Ctrl+O", childMenuItem.GetAttribute("AcceleratorKey"));
         }
 
-        [Fact]
+        [PlatformFact(SkipOnOSX = true)]
         public void PointerOver_Does_Not_Steal_Focus()
         {
             // Issue #7906