test: Generalize allow_failed_sudo_journal_messages()
test: Generalize allow_failed_sudo_journal_messages()

This has been a game of whack-a-rat, and there's still new messages
appearing, like "sudo: no valid sudoers sources found, quitting".

But this is non-sense: Simplifiy the function to allow *all* messages
from sudo; that's what we are effectively trying to do, and we only use
it in tests where we expect sudo to fail.

mvollmer/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit,garrett/cockpit,martinpitt/cockpit,martinpitt/cockpit,garrett/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit