Remove calls to `GetVersionEx`

With fix 0ca32249c1 and #2095 resolved, `GetVersionEx` is no longer required.

Microsoft.Toolkit.Win32.UI.Controls/Interop/OSVersionHelper.cs

@@ -125,8 +125,7 @@ namespace Microsoft.Toolkit.Win32.UI.Controls.Interop
         [SecurityCritical]
         private static bool IsServer()
         {
-            // RtlGetVersion does not return ProductType
-            var versionInfo = NativeMethods.GetVersionEx();
+            var versionInfo = NativeMethods.RtlGetVersion();
             return versionInfo.ProductType == ProductType.VER_NT_DOMAIN_CONTROLLER
                    || versionInfo.ProductType == ProductType.VER_NT_SERVER;
         }
@@ -167,7 +166,7 @@ namespace Microsoft.Toolkit.Win32.UI.Controls.Interop
                     throw new ArgumentException(DesignerUI.E_UNRECOGNIZED_OS, nameof(version));
             }
 
-            // After 8.1 apps without manifest or are not manifested for 8.1/10 return 6.2.
+            // After 8.1 apps without manifest or are not manifested for 8.1/10 return 6.2 when using GetVersionEx.
             // Need to use RtlGetVersion to get correct major/minor/build
             var os = NativeMethods.RtlGetVersion();
 

Microsoft.Toolkit.Win32.UI.Controls/Interop/Win32/NativeMethods.cs

@@ -59,29 +59,6 @@ namespace Microsoft.Toolkit.Win32.UI.Controls.Interop.Win32
         [DllImport(ExternDll.User32, ExactSpelling = true, CharSet = CharSet.Auto)]
         public static extern bool IsChild(HandleRef parent, HandleRef child);
 
-        [SecurityCritical]
-        [DllImport(ExternDll.Kernel32, SetLastError = true, EntryPoint = "GetVersionExW", CharSet = CharSet.Unicode)]
-        private static extern bool _GetVersionExW(ref OSVERSIONINFOEX osVersionInfo);
-
-        // With the release of Windows 8.1, the behavior of the GetVersionEx API has changed the
-        // value it will return for the OS version. The value returned now depends on how the application
-        // is manifested.
-        //
-        // Applications not manifested for for Windows 8.1 or Windows 10 will return the Windows 8 OS
-        // version value of 6.2. Once an application is manifested for a given OS version, GetVersionEx
-        // will always return the version that the application is manifested for in future releases.
-        [SecurityCritical]
-        public static OSVERSIONINFOEX GetVersionEx()
-        {
-            var osVersionInfo = new OSVERSIONINFOEX { OSVersionInfoSize = Marshal.SizeOf(typeof(OSVERSIONINFOEX)) };
-            if (!_GetVersionExW(ref osVersionInfo))
-            {
-                HRESULT.ThrowLastError();
-            }
-
-            return osVersionInfo;
-        }
-
         [SecurityCritical]
         [DllImport(ExternDll.Ntdll, SetLastError = true, EntryPoint = "RtlGetVersion")]
         private static extern bool _RtlGetVersion(ref OSVERSIONINFOEX versionInfo);