networkmanager: Connect to firewalld as superuser
networkmanager: Connect to firewalld as superuser

This makes the page work when connecting as a user which has sudo, but
not polkit privileges. (I. e. when they are not in the `wheel` group,
but have an explicit user sudo rule).

https://bugzilla.redhat.com/show_bug.cgi?id=1664158
Closes #10926
deryni/cockpit,andreasn/cockpit,garrett/cockpit,cockpituous/cockpit,mvollmer/cockpit,garrett/cockpit,moraleslazaro/cockpit,andreasn/cockpit,cockpituous/cockpit,andreasn/cockpit,moraleslazaro/cockpit,garrett/cockpit,andreasn/cockpit,cockpituous/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,deryni/cockpit,cockpituous/cockpit,cockpit-project/cockpit,mvollmer/cockpit,deryni/cockpit,andreasn/cockpit,martinpitt/cockpit,garrett/cockpit,cockpit-project/cockpit,andreasn/cockpit,martinpitt/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,deryni/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,deryni/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,deryni/cockpit,moraleslazaro/cockpit,garrett/cockpit,cockpit-project/cockpit,deryni/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,andreasn/cockpit