Unclear message when querying by ID in REST for work item that does not exist

[rjmurillo]

Repro

var authType = AuthenticationTypes.PersonalAccessToken;
var options = new AuthenticationOptions(uri, authType, types => new VssCredentials[] { cred });
var fac = Microsoft.Qwiq.Client.Rest.WorkItemStoreFactory.Default;
var wis = fac.Create(options);
wis.Query(12345);

System.ArgumentNullException
Value cannot be null. Parameter name: item

   at Microsoft.Qwiq.Client.Rest.WorkItem..ctor(WorkItem item, Lazy`1 wit, Func`2 linkFunc)
   at Microsoft.Qwiq.Client.Rest.Query.CreateItemLazy(WorkItem workItem)
   at Microsoft.Qwiq.Client.Rest.Query.<RunQueryImplLazy>d__21.MoveNext()
   at Microsoft.Qwiq.ReadOnlyObjectWithNameCollection`1.Ensure()
   at Microsoft.Qwiq.ReadOnlyObjectWithNameCollection`1.GetEnumerator()
   at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source)
   at Microsoft.Qwiq.Client.Rest.WorkItemStore.Query(Int32 id, Nullable`1 asOf)
   at Castle.Proxies.Invocations.IWorkItemStore_Query_2.InvokeMethodOnTarget()
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at Microsoft.Qwiq.Exceptions.ExceptionHandlingDynamicProxy.Intercept(IInvocation invocation)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Qwiq.Exceptions.ExceptionHandlingDynamicProxy.Intercept(IInvocation invocation)
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at Castle.Proxies.IWorkItemStoreProxy.Query(Int32 id, Nullable`1 asOf)