[az] Inconsistent VM state after `disable-zones`

[sharder996]

If a backend driver does not have the suspend VM operation implemented, VMs are turned off and displayed as being Stopped instead of Unavailable.

This only really affects the applevz driver AFAIK, so the priority should be reflected as such.

scott@Scotts-MacBook-Pro Downloads % multipass ls
Name                    State             IPv4             Image               Zone
bar                     Stopped           --               Ubuntu 26.04 LTS    zone1(n/a)
foo                     Stopped           --               Ubuntu 26.04 LTS    zone1(n/a)
scott@Scotts-MacBook-Pro Downloads % multipass get local.driver
applevz
...
scott@Scotts-MacBook-Pro Downloads % multipass ls
Name                    State             IPv4             Image               Zone
bar                     Unavailable       --               Ubuntu 26.04 LTS    zone1(n/a)
foo                     Unavailable       --               Ubuntu 26.04 LTS    zone1(n/a)
scott@Scotts-MacBook-Pro Downloads % multipass get local.driver
qemu

[sharder996]

After some checking, it seems suspend isn't used during the disable-zones operation, so its unclear where the difference in behaviour comes from between the qemu and applevz drivers.

[ricab]

Even though AppleVZ is in preview, I tend to think this should be fixed before 1.17, to avoid adding confusion in the zones feature, which may already be puzzling for some.

@sharder996 I am moving to that milestone, if only to flag it for discussion in the meeting. We can decide to revert then.