win32/filesystem: use CreateFileW with FILE_SHARE_DELETE in vlc_open()

So the file can be renamed while we read it ¹.

The file permission creation mode is not used anymore. Only 0666 and 0600 were used.

Fixes #19700.

1. https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew#file_share_delete ↩