[Cashtab] Upgrade to latest chronik-client

Summary:
T2501

Upgrade to latest version of chronik-client and remove protobufjs

Test Plan:
npm start
Test websocket incoming tx notifications
npm run build and no errors

Reviewers: #bitcoin_abc, kieran709

Reviewed By: #bitcoin_abc, kieran709

Differential Revision: https://reviews.bitcoinabc.org/D11621