Microsoft.NETCore.Platforms: fix graph not being updated on pack. (#82204)

Author: tmds

src/libraries/Microsoft.NETCore.Platforms/src/Microsoft.NETCore.Platforms.csproj

@@ -17,7 +17,8 @@
     <AvoidRestoreCycleOnSelfReference>true</AvoidRestoreCycleOnSelfReference>
     <!-- TODO: Remove with AvoidRestoreCycleOnSelfReference hack. -->
     <PackageValidationBaselineName>$(MSBuildProjectName)</PackageValidationBaselineName>
-    
+    <BeforePack Condition="'$(AdditionalRuntimeIdentifiers)' == ''">UpdateRuntimeJson;$(BeforePack)</BeforePack>
+
     <_generateRuntimeGraphTargetFramework Condition="'$(MSBuildRuntimeType)' == 'core'">$(NetCoreAppToolCurrent)</_generateRuntimeGraphTargetFramework>
     <_generateRuntimeGraphTargetFramework Condition="'$(MSBuildRuntimeType)' != 'core'">net472</_generateRuntimeGraphTargetFramework>
     <_generateRuntimeGraphTask>$([MSBuild]::NormalizePath('$(BaseOutputPath)', $(Configuration), '$(_generateRuntimeGraphTargetFramework)', '$(AssemblyName).dll'))</_generateRuntimeGraphTask>