When tailscaled gets started with userspace networking, it won't
modify your system's network configuration. For this, it creates
a noopManager for DNS management. noopManager correctly observes
that there's no real OS DNS to send queries to. This leads to we
completely dropping any DNS internal resolution from `dns query`
This change alters this so that even without a base config we'll
still allow the internal resolver to handle internal DNS queries
Fixes#18354
Signed-off-by: Fernando Serboncini <fserb@tailscale.com>
214b70cc1a