.Net Agents - Fix agent runtime package publishing (#12171)

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Include `nuget-package.props`

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Include is required.

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Author: crickman

dotnet/src/Agents/Runtime/Abstractions/Runtime.Abstractions.csproj

@@ -8,6 +8,8 @@
     <VersionSuffix>preview</VersionSuffix>
     <DefineConstants>SKIPSKABSTRACTION</DefineConstants>
   </PropertyGroup>
+
+  <Import Project="$(RepoRoot)/dotnet/nuget/nuget-package.props" />
 
   <ItemGroup>
     <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/src/System/*" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />

dotnet/src/Agents/Runtime/Core/Runtime.Core.csproj

@@ -8,6 +8,8 @@
     <DefineConstants>SKIPSKABSTRACTION</DefineConstants>
   </PropertyGroup>
 
+  <Import Project="$(RepoRoot)/dotnet/nuget/nuget-package.props" />
+
   <ItemGroup>
     <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/src/System/*" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />
     <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/src/Diagnostics/NullableAttributes.cs" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />