Previously, running `tailscale lock log` in a tailnet without Tailnet
Lock enabled would return a potentially confusing error:
$ tailscale lock log
2025/10/20 11:07:09 failed to connect to local Tailscale service; is Tailscale running?
It would return this error even if Tailscale was running.
This patch fixes the error to be:
$ tailscale lock log
Tailnet Lock is not enabled
Fixes#17586
Signed-off-by: Alex Chan <alexc@tailscale.com>