Detect if IP-PREFIX is assigned to loopback interface
Detect if IP-PREFIX is assigned to loopback interface

Before if IP-PREFIX is removed from loopback interface
healthcheck was successful as the check was hitting another box.
Now, we detect if IP-PREFIX is removed from lo interface and declare
the service as DOWN but without removing the IP-PREFIX from bird
configuration as direct1 protocol has already removed the route for
that IP-PREFIX which triggered upstream routers to withdrawn the specific
route

unixsurfer/anycast_healthchecker,unixsurfer/anycast_healthchecker,unixsurfer/anycast_healthchecker