net: Keep trying to use UPnP when -upnp=1
Summary:
This is a backport of core#18077 [3/13]
https://github.com/bitcoin/bitcoin/pull/18077/commits/8b50d1b5bb29b7d1ea0245ba75a8df3144e312dc
Depends on D12070
Test Plan: ninja all check-all
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D12072