Clear m_addr_known before our periodic self-advertisement
Summary:
This behavior was apparently inadvertently broken in 5400ef6; without this change our daily self-announcements frequently go unsent, because our address is still in the peer's rolling bloom filter (for potentially many days, depending on addr traffic).
Backport of core#20561.
Ref T1696.
Test Plan:
ninja all check-all
Reviewers: #bitcoin_abc, PiRK
Reviewed By: #bitcoin_abc, PiRK
Maniphest Tasks: T1696
Differential Revision: https://reviews.bitcoinabc.org/D10859