GetDetailedGrainStatistics is not shown StatelessWorker

some code from tests.
In general, there is no StatelessWorker Grains in GetDetailedGrainStatistics, but GetSimpleGrainStatistics has them.

``` cs
await _cluster.Cluster.StartAdditionalSiloAsync();
for (int i = 0; i < 100_000; I++)
{
await _cluster.Cluster.Client.GetGrain("1").Do(); // [StatelessWorker(10)]
await _cluster.Cluster.Client.GetGrain("2").Count(); // Grain
}

var hosts = await _cluster.Cluster.Client.GetGrain(0).GetHosts();

Dictionary result = new Dictionary();
foreach (var host in hosts)
{
var activations = await _cluster.Cluster.Client.GetGrain(0).GetDetailedGrainStatistics(null, new []{host.Key});
result.Add(result.Count, activations.Where(w=>w.GrainType.Contains("PerSiloGrain") || w.GrainType.Contains("MetricGrain")).ToArray());
}

var x = PerSiloGrain.ActivationCount; //1
```

Start by reproducing the shown scenario with StartAdditionalSiloAsync, PerSiloGrain, MetricGrain, and GetDetailedGrainStatistics. Compare the results from GetDetailedGrainStatistics with GetSimpleGrainStatistics for each host. Done means StatelessWorker grain activations appear in the detailed statistics consistently with the simple statistics.

Written by the indexing model from the issue text.