Don't build ANCM forwarders in VMR (#61000)

Author: wtgodbe

src/Installers/Windows/AspNetCoreModule-Setup/ANCMIISExpressV2/AncmIISExpressV2.wixproj

@@ -95,7 +95,7 @@
                       '$(PackageLicenseExpression)' " />
   </Target>
 
-  <Target Name="BeforeBuild" Condition="'$(Platform)' == 'arm64'">
+  <Target Name="BeforeBuild" Condition="'$(Platform)' == 'arm64' AND '$(DotNetBuild)' != 'true'">
     <MSBuild Projects="..\Forwarders\build.proj" />
   </Target>
 </Project>