download_dml.py failed on branch webnn_mojo branch

[halton]

Checkout webnn_mojo branch, and run gclient runhooks, it will failed on download_dml_unpkg hook.

python3.bat src/content/browser/ml/webnn/dml/download_dml.py
downloading https://api.nuget.org/v3-flatcontainer/microsoft.ai.directml/1.8.2/microsoft.ai.directml.1.8.2.nupkg
Traceback (most recent call last):
  File "src/content/browser/ml/webnn/dml/download_dml.py", line 71, in <module>
    sys.exit(main())
  File "src/content/browser/ml/webnn/dml/download_dml.py", line 68, in main
    download_nupkg(dml_feed_url, dml_resource_id, dml_resource_version, dml_path)
  File "src/content/browser/ml/webnn/dml/download_dml.py", line 53, in download_nupkg
    with open(resource_file, 'wb') as file:
FileNotFoundError: [Errno 2] No such file or directory: 'C:\\Edge\\src\\content\\browser\\ml\\webnn\\dml\\../../../../../../third_party\\microsoft.ai.directml.1.8.2.nupkg'

Root cause: the path of C:\\Edge\\src\\content\\browser\\ml\\webnn\\dml\\../../../../../../third_party is wrong.