Try to exclude Ref package

This should be excluded already, and is already excluded locally not sure why it's being built on the CI

Author: =

eng/Build.props

@@ -154,8 +154,8 @@
                           $(RepoRoot)src\Analyzers\**\*.csproj;
                           $(RepoRoot)src\ProjectTemplates\*\*.csproj;
                           $(RepoRoot)src\ProjectTemplates\testassets\*\*.csproj;
-                          " />
-        <DotNetProjects Remove="
+                          "
+                        Exclude="
                           @(ProjectToBuild);
                           @(ProjectToExclude);
                           $(RepoRoot)**\node_modules\**\*;

src/Framework/ref/Microsoft.AspNetCore.App.Ref.csproj

@@ -6,6 +6,8 @@
     <IsShippingPackage>true</IsShippingPackage>
     <IsPackable>true</IsPackable>
     <IsPackable Condition="'$(IsTargetingPackBuilding)' == 'false'">false</IsPackable>
+    <!-- Exclude this project from source build -->
+    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
     <PackageId>$(TargetingPackName)</PackageId>
     <VersionPrefix>$(TargetingPackVersionPrefix)</VersionPrefix>