net: Pass onion service target to Tor controller

Summary:
This is a backport of core#19991 [5/8]
https://github.com/bitcoin/bitcoin/pull/19991/commits/57f17e57c8c410e10c16a46f7372c0ea8b7dd467

Depends on D10447

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D10448