fix condition emscripten + vcpkg

Author: fs-eire

cmake/CMakeLists.txt

@@ -1067,7 +1067,7 @@ if (onnxruntime_USE_WEBGPU)
   list(APPEND ORT_PROVIDER_FLAGS -DUSE_WEBGPU=1)
   list(APPEND ONNXRUNTIME_PROVIDER_NAMES webgpu)
 
-  if (onnxruntime_USE_VCPKG)
+  if (onnxruntime_USE_VCPKG AND NOT CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
     if (NOT onnxruntime_BUILD_DAWN_MONOLITHIC_LIBRARY)
       message(FATAL_ERROR "onnxruntime_USE_VCPKG is not supported with onnxruntime_BUILD_DAWN_MONOLITHIC_LIBRARY=OFF")
     endif()