[Cashtab] [airdrop chronik for mint address p2/2] Deprecate bch-api for getting minting address

Summary:
T2730

Depends on D12367

Remove bch-api approach and debug logging

Test Plan:
npm start
Create a few airdrop txs with 'ignore minting address' clicked and confirm they work ok

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D12368