Prepare JSON helper packages for release (Azure#17827)

Author: heaths

sdk/core/Microsoft.Azure.Core.NewtonsoftJson/src/Microsoft.Azure.Core.NewtonsoftJson.csproj

@@ -10,11 +10,6 @@
     <EnableClientSdkAnalyzers>false</EnableClientSdkAnalyzers>
   </PropertyGroup>
 
-  <ItemGroup>
-    <!-- TODO: Remove before release -->
-    <ProjectReference Include="../../Azure.Core/src/Azure.Core.csproj" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" />
   </ItemGroup>
@@ -23,4 +18,6 @@
   <ItemGroup>
     <Compile Include="$(AzureCoreSharedSources)Argument.cs" Link="Shared\%(RecursiveDir)\%(Filename)%(Extension)" />
   </ItemGroup>
+
+  <Import Project="$(MSBuildThisFileDirectory)..\..\Azure.Core\src\Azure.Core.props" />
 </Project>

sdk/core/Microsoft.Azure.Core.NewtonsoftJson/src/NewtonsoftJsonObjectSerializer.cs

@@ -3,8 +3,6 @@
 
 using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using System.IO;
 using System.Reflection;
 using System.Text;

sdk/core/Microsoft.Azure.Core.NewtonsoftJson/tests/Samples/Readme.cs

@@ -7,8 +7,6 @@
 using Azure.Core.Serialization;
 using Azure.Core.TestFramework;
 using Azure.Search.Documents;
-using Azure.Search.Documents.Indexes;
-using Azure.Search.Documents.Indexes.Models;
 using Azure.Search.Documents.Models;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Converters;