[ecash-herald] Patch import error for secrets

Summary:
T2972

This is an artifact from when the app was being developed and put into production locally. secrets.js should be in the top level like config, not above the top level.

Test Plan: node index.js and no errors (if you have secrets.js with telegram bot info). Otherwise, confirm README specifies secrets.js should go in same dir as config.js

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D14173