Regular relays are about to get their DirPort removed so that reachability
test is not useful anymore

Authorities will still use the DirPort but because network reentry towards
their DirPort is now denied network wide, this test is not useful anymore and
so it should simply be considered reachable at all time.

Part of #40282



Signed-off-by: David Goulet <dgoulet@torproject.org>