WiX 5 update (#15867)

Author: joeloff

src/Microsoft.DotNet.Arcade.Sdk/tools/DefaultVersions.props

@@ -99,7 +99,7 @@
     <MicrosoftManifestToolCrossPlatformVersion Condition="'$(MicrosoftManifestToolCrossPlatformVersion)' == ''">2.1.3</MicrosoftManifestToolCrossPlatformVersion>
     <MicrosoftVisualStudioEngMicroBuildPluginsSwixBuildVersion Condition="'$(MicrosoftVisualStudioEngMicroBuildPluginsSwixBuildVersion)' == ''">1.1.286</MicrosoftVisualStudioEngMicroBuildPluginsSwixBuildVersion>
     <MicrosoftSignedWixVersion Condition="'$(MicrosoftSignedWixVersion)' == ''">3.14.1-9323.2545153</MicrosoftSignedWixVersion>
-    <MicrosoftWixToolsetVersion Condition="'$(MicrosoftWixToolsetVersion)' == ''">5.0.2-dotnet.2690783</MicrosoftWixToolsetVersion>
+    <MicrosoftWixToolsetVersion Condition="'$(MicrosoftWixToolsetVersion)' == ''">5.0.2-dotnet.2718840</MicrosoftWixToolsetVersion>
   </PropertyGroup>
 
   <!-- RestoreSources overrides - defines DotNetRestoreSources variable if available -->

src/Microsoft.DotNet.Build.Tasks.Installers/build/wix5/bundle/upgradePolicies.wxs

@@ -1,5 +1,5 @@
 <!-- Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. -->
-<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs" xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util">
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs" xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util">
   <Fragment>
     <!-- Bundle variables become unset if a search fails. The global key is retrieved first. If this fails,
          RemoveUpgradeRelatedBundle becomes unset, allowing the version specific search to potentially set