relay: Don't lookup our address before rebuilding our descriptor

Tor periodic events have moved to a role base model where relays have specific
events. One of those is to rebuild the descriptor and that is ran every
minute.

This removes the call to router_rebuild_descriptor() from
router_get_my_routerinfo_with_err() because that is the only code path that
can call for a rebuild every second.

Instead, when we mark the descriptor as dirty, immediately reschedule the
descriptor check periodic event so it can be rebuilt that way instead of
randomly when router_get_my_routerinfo_with_err() is called.

Related to #40025

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