Treat all extorport connections with un-set addresses as remote

Without this fix, if an PT forgets to send a USERADDR command, that results in a connection getting treated as local for the purposes of rate-limiting.

If the PT does use USERADDR, we still believe it.

Closes #33747 (closed).

This patch is against maint-0.3.5; let's not close it until it is fully backported.