[chronik] Determine lokad indexing by enable_lokad_id_index param

Summary:
Typo bug where enabling the lokad index is determined by the enable_token_index param

Patch so the enable_lokad_id_index param behaves as expected

Test Plan:

mkdir buildChronik
pushd buildChronik
cmake -GNinja .. -DBUILD_BITCOIN_CHRONIK=ON
ninja
ninja check-functional
cd test/functional
./test_runner.py chronik_lokad_id_group

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16416