QA: Use getblocktemplate to get block versions correct
Summary:
This is a backport of core#19401 [2/2]
https://github.com/bitcoin/bitcoin/pull/19401/commits/d438d609cd64fe532d94e45000495de93ef99aa6
Depends on D10688
Test Plan: ninja check-functional
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D10689