Previous working rule "mount options=(rw, rslave) /," fails with apparmor 3.1.4

We see integration test failures on arch linux related to apparmor, e.g. https://github.com/snapcore/snapd/actions/runs/5186349409/jobs/9347774708?pr=12870

It looks like it's this rule:
```
mount options=(rw, rslave) /,
```

The error is the following:
```
...
2023-06-06T08:59:58.6472304Z error: cannot perform the following tasks:
2023-06-06T08:59:58.6473193Z - Connect network-control-consumer:network-control to core:network-control (cannot setup profiles for snap "network-control-consumer": cannot load apparmor profiles: exit status 1
2023-06-06T08:59:58.6473774Z apparmor_parser output:
2023-06-06T08:59:58.6474032Z Encoding of mount rule failed
2023-06-06T08:59:58.6474551Z ERROR processing policydb rules for profile snap.network-control-consumer.cmd, failed to load
2023-06-06T08:59:58.6474944Z )
...
2023-06-06T08:59:59.5091838Z + apparmor_parser --version
2023-06-06T08:59:59.5093210Z AppArmor parser version 3.1.4
...
```

the profile is here: https://paste.ubuntu.com/p/fQ8bv6VvWG/ - and apparmor_parser --debug here https://paste.ubuntu.com/p/dvxX9Xd9yZ/ (but that does not give a failure oddly enough)

This might be releated to https://bugs.launchpad.net/apparmor/+bug/1648245

I created https://github.com/snapcore/snapd/pull/12871 to match the new behavior.