Update dependencies from https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int build 20210828.2 (#5214)

[release/6.0] Update dependencies from dnceng/internal/dotnet-wpf-int

eng/Version.Details.xml

@@ -49,9 +49,9 @@
       <Uri>https://github.com/dotnet/runtime</Uri>
       <Sha>fedf1bf8db1197925fd04a8534c6dae006fe7114</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="6.0.0-rc.2.21425.2">
+    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="6.0.0-rc.2.21428.2">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int</Uri>
-      <Sha>a163d8a9b683056c3334d13f0513bbb2c371f3e9</Sha>
+      <Sha>39b3aeccd1bea6b158e239db301ab23e365740d3</Sha>
     </Dependency>
     <Dependency Name="System.IO.Packaging" Version="6.0.0-rc.2.21428.1" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>

eng/Versions.props

@@ -80,6 +80,6 @@
     <SystemReflectionMetadataLoadContextPackage>System.Reflection.MetadataLoadContext</SystemReflectionMetadataLoadContextPackage>
   </PropertyGroup>
   <PropertyGroup>
-    <MicrosoftDotNetWpfDncEngVersion>6.0.0-rc.2.21425.2</MicrosoftDotNetWpfDncEngVersion>
+    <MicrosoftDotNetWpfDncEngVersion>6.0.0-rc.2.21428.2</MicrosoftDotNetWpfDncEngVersion>
   </PropertyGroup>
 </Project>