Debug visualizer does not expand nested runtime class properties - VS2019/VS2022 regression

[Scottj1s]

When the debug visualizer was first released with VS2017, it would expand nested runtime class properties. With VS2019/VS2022, this functionality no longer works.

Repro:

1. Install the C++/WinRT VS extension in VS 2019 or VS 2022 (despite the name, it supports both).
2. Create a simple C++/WinRT console app from the extension template, and add a query parameter to the uri:

#include "pch.h"

using namespace winrt;
using namespace Windows::Foundation;

int main()
{
    init_apartment();
    Uri uri(L"http://aka.ms/cppwinrt?foo=bar");
    printf("Hello, %ls!\n", uri.AbsoluteUri().c_str());
}

3. Set a BP on the printf
4. Build and F5 to debug
5. In a watch window, type "uri"
6. Expand the visualization for uri
7. Expand the nested visualization for the QueryParsed property

Expected results:
The QueryParsed.Size property should be displayed, with value '1'

Actual results:
No expansion of QueryParsed occurs.

Notes:

In debugging the app with VS2017, the expansion results in BPs on both cppwinrt_visualizer::GetChildren and cppwinrt_visualizer::GetItems being hit. But with VS2019/VS2022, only cppwinrt_visualizer::GetChildren gets called - cppwinrt_visualizer::GetItems is never called and no child items (properties) are displayed.