hs-v3: Handle client rendezvous circuit timeout

With v3, the "pending_final_cpath" of a circuit is always NULL which means
that for v3, established client rendezvous circuit waiting for the intro point
to ACK, will always end up timing out quickly.

This can increase the delays to which you connect to a service since in order
to succeed, the rendezvous circuit needs to fully established
(CIRCUIT_PURPOSE_C_REND_JOINED) within the cutoff of the introduction circuit
as well which is these days around 2-3 seconds.

Fixes #32021

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