refactor: Replace uses ChainActive() in interfaces/chain.cpp
Summary:
This is a backport of core#19425 [2/3]
https://github.com/bitcoin/bitcoin/pull/19425/commits/6965f1352d2d7086d308750ce83a84f191a17755
Depends on D11418
Test Plan: ninja all check-all
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D11419