We want users to have the freedom to start tailscaled with `-no-logs-no-support`,
but that is obviously in direct conflict with tailnets that have network logging
enabled.
When we detect that condition, we record the issue in health, notify the client,
set WantRunning=false, and bail.
We clear the item in health when a profile switch occurs, since it is a
per-tailnet condition that should not propagate across profiles.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>