hs: Remove EnableOnionServiceV3 consensus param

As of #19899, we decided to allow any relay understanding the onion service
version 3 protocol to be able to use it. The service and client will be the
one controlled by a consensus parameter (different one for both of them) but
if you are a relay and you can understand a protocol, basically you should use
the feature.

Closes #19899

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