Previously, we used a non-nil Location as an indicator that a peer is a Mullvad exit node.
However, this is not, or no longer, reliable, since regular exit nodes may also have a non-nil Location,
such as when traffic steering is enabled for a tailnet.
In this PR, we update the plaintext `tailscale status` output to omit only Mullvad exit nodes, rather than all
exit nodes with a non-nil Location. The JSON output remains unchanged and continues to include all peers.
Updates tailscale/corp#30614
Signed-off-by: Nick Khyl <nickk@tailscale.com>
c87f44b687