HPCC-9045 WSFileIO is not accessible by non-admin users

Security descriptors for "FileIOAccess" were incorrectly validated in
ws_fileioservice.cpp against the string "FileIO", resulting in failures
every time (unless requested by an admin). This fix corrects the string
in ws_fileioservice.cpp to the same one that is provided in the request

Signed-off-by: William Whitehead <william.whitehead@lexisnexis.com>