This is a step toward removing the Chain::Lock class and reducing cs_main
It also helps ensure the GUI display stays up to date in the case where the
node chain height runs ahead of wallet last block processed height.
This is part [2/12] of Core PR17954 : https://github.com/bitcoin/bitcoin/pull/17954/commits/f6da44ccce4cfff53433e665305a6fe0a01364e4
Depends on D7864