Update dependencies from https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int build 20210819.4 (#5123)

[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>5a5d7f0518b564e7f840c6c939bb6618c778b21b</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="6.0.0-rc.2.21418.6">
+    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="6.0.0-rc.2.21419.4">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int</Uri>
-      <Sha>ae89dd52d768a5419941430aeb2fa0594e89e97d</Sha>
+      <Sha>33e5e96f9f0138f39235a3d283b51e71b215a767</Sha>
     </Dependency>
     <Dependency Name="System.IO.Packaging" Version="6.0.0-rc.2.21417.16" 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.2.21418.6</MicrosoftDotNetWpfDncEngVersion>
+    <MicrosoftDotNetWpfDncEngVersion>6.0.0-rc.2.21419.4</MicrosoftDotNetWpfDncEngVersion>
   </PropertyGroup>
 </Project>