Use template function instead of void* parameter

Summary:
This change gets rid of -Wthread-safety-attributes warning spam.

This is part [3/5] of Core PR18635 : https://github.com/bitcoin/bitcoin/pull/18635/commits/971a468ccf0474ca00fa7d20278569b8fb11f0fb

Depends on D7878

Test Plan:

ninja all check

Checks that clang thread safety analysis is happy.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D7879