qa: Disable a test for kernel mount

qa: Disable a test for kernel mount

The kclient fix isn't yet landed in the kernel and hence
the test 'test_multifs_single_client_cross_access_r_caps_end'
would fail for kernel mount. So disable the failing validation
in the test for kclient.

Fixes: https://tracker.ceph.com/issues/72167
Signed-off-by: Kotresh HR <khiremat@redhat.com>
(cherry picked from commit 485f37ac1fe7d233685ce1a1f9ac5360c142b1f5)

Conflicts:
   qa/tasks/cephfs/test_admin.py: The commit
  9d0ab233d822668e88c873bc1314e984feaf1296 is not backported