AppArmor is auditing the apparmor/.null file

AppArmor is creating unnecessary log spam

Files with a dentry pointing aa_null.dentry where already rejected as
part of file_inheritance. Unfortunately the check in
common_file_perm() is insufficient to cover all cases causing
unnecessary audit messages without the original files context.

Eg.
[ 442.886474] audit: type=1400 audit(1704822661.616:329): apparmor="DENIED" operation="file_inherit" class="file" namespace="root//lxd-juju-98527a-0_<var-snap-lxd-common-lxd>" profile="snap.lxd.activate" name="/apparmor/.null" pid=9525 comm="snap-exec"

other examples can be found in the logs of
https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/2120439
https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1952084
https://bugs.launchpad.net/snapd/+bug/2049099