Added properties for the swap chain in the direct3d11 and direct3d12 renderers

Fixes https://github.com/libsdl-org/SDL/issues/9775

src/render/direct3d12/SDL_render_d3d12.c

@@ -1318,6 +1318,8 @@ static HRESULT D3D12_CreateSwapChain(SDL_Renderer *renderer, int w, int h)
         result = DXGI_ERROR_UNSUPPORTED;
     }
 
+    SDL_SetProperty(SDL_GetRendererProperties(renderer), SDL_PROP_RENDERER_D3D12_SWAPCHAIN_POINTER, data->swapChain);
+
 done:
     SAFE_RELEASE(swapChain);
     return result;