debian package has priority "required"

[debian control file](../blob/main/packaging/aznfs/DEBIAN/control#L3) has `Priority` field set to "required".

[According to docs](https://www.debian.org/doc/debian-policy/ch-archive.html#s-priorities) this is reserved for packages that are needed for dpkg to be able to install other packages (so the bare minimum needed before your system becomes unrecoverable).

This causes debootstrap/mmdebstrap and similar tools to install this package if it is made available. As it was added to microsoft debian repository on Friday, this got rolled out to a lot of people implicitly, e.g. via https://packages.microsoft.com/debian/13/prod/dists/trixie/main/binary-amd64/Packages

I can only imagine this was not intended, and it does affect our specific case where we need this repository, but the server build fails to set up the build environment now (it runs in a docker container, so aznfs complains that it cannot be installed without systemd, or sometimes it can't find dependencies...).

The default priority is "optional" and the docs suggest to simply omit this field entirely, so that is my suggestion.

Open packaging/aznfs/DEBIAN/control at the Priority field referenced in the issue and review the Debian package metadata. Change the priority handling to match Debian's optional default, then verify that the generated package no longer causes debootstrap or mmdebstrap to install it implicitly.

Written by the indexing model from the issue text.