[token-server] Add debug log for troubleshooting admin token bot

Summary: This feature works locally but is not working in prod. I'm not sure why. Add debug logs so I can run some tests with the prod server.

Test Plan: Confirm this diff only adds logs. npm test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D15832