hs-v2: Warn of v2 obsolete if configured

For a user using "HiddenServiceVersion 2", a log warning is emitted indicating
that v2 is now obsolete instead of a confusing message saying that the version
is not supported.

Also, if an introduction point gets a legacy (v2) ESTABLISH_INTRO, we'll
simply close the circuit without emitting a protocol warning log onto the
relay.

Related to #40266

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