i/b/mount-control: add optional `/` to umount rules (#12168)
* i/b/mount-control: add optional `/` to umount rules
In commit a10ecaaaafc0aeaac59d563fc08cc6ba0ad75f1a we added an optional
`/` at the end of the AppArmor mount rules, since AppArmor is rather
strict on them.
Indeed, the same applies to umount rules.
* tests: improve mount-control spread tests
Diversify the paths in the "where" attributes, otherwise a
value like "$SNAP_COMMON/**" would hide potential errors in the "where"
attributes of other mount entries -- as indeed has been the case until
now, when we realized of the `/` missing at the end of the umount rules
(see the previous commit).
* tests: improve mount-control tests with review comments
Add a "/" to a mount point to verify that it's irrelevant.
interfaces/builtin/system-observe: extend access for htop
* Allow read access to /proc/sys/kernel/sched_autogroup_enabled and
/proc/*/{,task/*/}autogroup to show AGRP (autogroup) and ANI
(autogroup nice) columns.
* Allow read access to /proc/*/{,task/*/}io for detailed process IO
stats.
devicestate: add more path to `fixupWritableDefaultDirs()`
There is a use-case for fixupWritableDefaultDirs() to include
the dirs:
```
- /etc/systemd/network
```
to support rename to predicable network names. Eventually this
is something that snapd/netplan will support but to unblock
users this workaround is needed.