CVE-2023-4091: smbd: use open_access_mask for access check in open_file()

CVE-2023-4091: smbd: use open_access_mask for access check in open_file()

If the client requested FILE_OVERWRITE[_IF], we're implicitly adding
FILE_WRITE_DATA to the open_access_mask in open_file_ntcreate(), but for the
access check we're using access_mask which doesn't contain the additional
right, which means we can end up truncating a file for which the user has
only read-only access via an SD.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15439

Signed-off-by: Ralph Boehme <slow@samba.org>