EventGridNamespaceClientResource Not found in Azure.ResourceManager.Resources;

### Link to sample

https://learn.microsoft.com/en-us/rest/api/eventgrid/controlplane/clients/create-or-update?view=rest-eventgrid-controlplane-2023-12-15-preview&tabs=dotnet#examples

### Library name and version

Azure.ResourceManager 1.11.0

### Language of the Sample

- [X] C#/.NET
- [ ] Java
- [ ] JavaScript/TypedScript
- [ ] Python
- [ ] Golang
- [ ] Other - Please specify in Issue details field

### Sample Issue Type

- [X] Sample not working
- [X] Sample missing
- [ ] Do not understand sample

### Issue details

ResourceIdentifier eventGridNamespaceClientResourceId = **EventGridNamespaceClientResource**.CreateResourceIdentifier(subscriptionId, resourceGroupName, namespaceName, clientName);
EventGridNamespaceClientResource eventGridNamespaceClient = client.GetEventGridNamespaceClientResource(eventGridNamespaceClientResourceId);

// invoke the operation
EventGridNamespaceClientData data = new EventGridNamespaceClientData()
{
Description = "This is a test client",
ClientCertificateAuthentication = new ClientCertificateAuthentication()
{
ValidationScheme = ClientCertificateValidationScheme.SubjectMatchesAuthenticationName,
},
State = EventGridNamespaceClientState.Enabled,
Attributes =
{
["deviceTypes"] = BinaryData.FromObjectAsJson(new object[] { "Fan", "Light", "AC" }),
["floor"] = BinaryData.FromString("\"3\""),
["room"] = BinaryData.FromString("\"345\""),
},
};
ArmOperation lro = await eventGridNamespaceClient.UpdateAsync(WaitUntil.Completed, data);
EventGridNamespaceClientResource result = lro.Value;

// the variable result is a resource, you could call other operations on this instance as well
// but just for demo, we get its data from this resource instance
EventGridNamespaceClientData resourceData = result.Data;

### Expected behavior

_No response_

### Actual behavior

_No response_

### Reproduction Steps

_No response_

### Environment

_No response_