firewall: make the "Failed to add service" error message dynamic
firewall: make the "Failed to add service" error message dynamic

Similar condition exists for the modal dialog title.

Closes #12081
cockpituous/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,garrett/cockpit,deryni/cockpit,cockpit-project/cockpit,mvollmer/cockpit,garrett/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpituous/cockpit,deryni/cockpit,deryni/cockpit,mvollmer/cockpit,deryni/cockpit,mvollmer/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpituous/cockpit,mvollmer/cockpit,martinpitt/cockpit,deryni/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,garrett/cockpit,cockpit-project/cockpit,garrett/cockpit,cockpituous/cockpit,martinpitt/cockpit,garrett/cockpit,moraleslazaro/cockpit,deryni/cockpit