[Cashtab] [chronik tx history p16]Remove legacy amountSent and amountReceived

Summary:
T2447

Depends on D12144

Remove two legacy parameters and replace them with xecAmount parameter.

Test Plan:
Review unit test changes and npm test
npm start, send and receive XEC txs, see they are parsed correctly in tx history

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D12145