addr: Make resolve_my_address_v4() use find_my_address()

In order to transition smoothly, maek resolve_my_address_v4() call the new
fancy find_my_address() with AF_INET.

Next commits should remove the use of resolve_my_address_v4() accross the code
to use find_my_address().

This commit is so the unit tests would be more easily fixed and port to the
new find_my_address() internals.

Part of #33233.

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