LU-17289 test: disable sanity/test_906 temporarily

LU-17289 test: disable sanity/test_906 temporarily

On the rhel9.3, the fio io_uring engine testing failed with error
"Operation not permitted" on both local file systems (Ext4 and
xfs) and Lustre:
"fio: pid=4551, err=1/file:engines/io_uring.c:1047,
func=io_queue_init, error=Operation not permitted"

This is a generic failure in rhel9.3.
Thus we disable sanity/test_906 temporarily until the bug is fixed
in rhel9.3.

Test-Parameters: trivial
Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: I3805b475c5f3d0b62dc6c57c4cd93f2bc1b67b76