T2972
Depends on D13616
Add unit tests for parseWebsocketMessage
These unit tests required a mock Telegram bot and improvements to chronikMock.js
For now, I think it's okay to maintain chronikMock.js as distinct files in both alias-server and ecash-herald. The incremental work in both apps is a good way to learn what features this mock needs. It will eventually be extended to Cashtab and live as a centralized dependency.