Weaken dxcore dependency (#24845)

### Description
<!-- Describe your changes. -->
Do a manual load of dxcore.dll so that old Windows versions are still
supported.

### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
#24771

---------

Co-authored-by: Copilot <[email protected]>

Author: skottmckay

cmake/onnxruntime_common.cmake

@@ -169,10 +169,6 @@ if(APPLE)
   target_link_libraries(onnxruntime_common PRIVATE "-framework Foundation")
 endif()
 
-if(MSVC)
-  target_link_libraries(onnxruntime_common PRIVATE dxcore.lib)
-endif()
-
 if(MSVC)
   if(onnxruntime_target_platform STREQUAL "ARM64")
     set(ARM64 TRUE)

onnxruntime/core/platform/windows/device_discovery.cc

@@ -362,13 +362,31 @@ std::unordered_map<uint64_t, DeviceInfo> GetDeviceInfoD3D12() {
   return device_info;
 }
 
+typedef HRESULT(WINAPI* PFN_DXCoreCreateAdapterFactory)(REFIID riid, void** ppvFactory);
+
 // returns LUID to DeviceInfo
 std::unordered_map<uint64_t, DeviceInfo> GetDeviceInfoDxcore() {
   std::unordered_map<uint64_t, DeviceInfo> device_info;
 
+  // Load dxcore.dll. We do this manually so there's not a hard dependency on dxcore which is newer.
+  wil::unique_hmodule dxcore_lib{LoadLibraryExW(L"dxcore.dll", nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32)};
+  if (!dxcore_lib) {
+    LOGS_DEFAULT(INFO) << "Failed to load dxcore.dll. Expected on older Windows version that do not support dxcore.";
+    return device_info;
+  }
+
+  auto pfnDXCoreCreateAdapterFactory = reinterpret_cast<PFN_DXCoreCreateAdapterFactory>(
+      GetProcAddress(dxcore_lib.get(), "DXCoreCreateAdapterFactory"));
+
+  if (!pfnDXCoreCreateAdapterFactory) {
+    // this isn't expected to fail so ERROR not WARNING
+    LOGS_DEFAULT(ERROR) << "Failed to get DXCoreCreateAdapterFactory function address.";
+    return device_info;
+  }
+
   // Get all GPUs and NPUs by querying WDDM/MCDM.
   wil::com_ptr<IDXCoreAdapterFactory> adapterFactory;
-  if (FAILED(DXCoreCreateAdapterFactory(IID_PPV_ARGS(&adapterFactory)))) {
+  if (FAILED(pfnDXCoreCreateAdapterFactory(IID_PPV_ARGS(&adapterFactory)))) {
     return device_info;
   }