Import Microsoft.Managed targets in Sdk.IL (#34124)

If Microsoft.Managed targets aren't imported, multitargeting is broken as the required `InnerBuildProperty` and `InnerBuildPropertyValues` properties aren't defined. Those properties are read by the Graph APIs to identify if a build is an outer or inner build and multiplexes on them.

Fixes #34123

Author: ViktorHofer

src/coreclr/src/.nuget/Microsoft.NET.Sdk.IL/targets/Microsoft.NET.Sdk.IL.Common.targets

@@ -6,8 +6,10 @@ Copyright (c) .NET Foundation. All rights reserved.
 ***********************************************************************************************
 -->
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildToolsPath)\Microsoft.Managed.Before.targets" />
 
   <Import Condition="'$(IsCrossTargetingBuild)' != 'true'" Project="$(MSBuildThisFileDirectory)Microsoft.NET.Sdk.IL.targets" />
   <Import Condition="'$(IsCrossTargetingBuild)' == 'true'" Project="$(MSBuildExtensionsPath)\Microsoft.Common.CrossTargeting.targets" />
-
+  
+  <Import Project="$(MSBuildToolsPath)\Microsoft.Managed.After.targets" />
 </Project>