"dynamic rendering is not supported" for dx12_dynamic_rendering on RTX 4070 Ti

Log: [ppx.log](https://github.com/google/bigwheels/files/14805917/ppx.log)

Running `dx12_dynamic_rendering` on Windows 11 with RTX 4070 Ti produces:

```
*** PPX ASSERT ***
Message : Cannot create a pipeline with dynamic render pass, dynamic rendering is not supported.
Condition : false
Function : ppx::grfx::GraphicsPipeline::Create
Location : C:\Users\Michael\Desktop\git\bigwheels\src\ppx\grfx\grfx_pipeline.cpp : 286
```

I think this is because my RTX 4070 Ti only has `D3D12_RENDER_PASS_TIER_0` support but `dx12::device::DynamicRenderingSupported` wants > TIER_0. However, the [docs](https://learn.microsoft.com/en-us/windows/win32/api/d3d12/ne-d3d12-d3d12_render_pass_tier) has this to say for TIER_0:

> The user-mode display driver hasn't implemented render passes, and so the feature is provided only via software emulation. Render passes might not provide a performance advantage at this level of support.

If I override `dx12::device::DynamicRenderingSupported` to return true then the program runs.

It is unclear to me why "dynamic rendering is not supported" for a tier that works