[net] remove fUpdateConnectionTime from FinalizeNode

Summary:

PeerManager can just call directly into CAddrMan::Connected() now.

Completes backport of core#20228:
https://github.com/bitcoin/bitcoin/pull/20228/commits/3fc06d3d7b43dc1143fe0850db23c4e7ffbfe682

Depends on D12250.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D12251