[ecash-herald] Tighten up daily summary msgs

Summary:
The non-agora token actions are not as interesting as I would have thought. Stop rendering them in prod.

Stop repeating the 'buy list cancel' key, once is plenty.

Test Plan:
npm test, review new look

before:

after:

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D17293