Log UnicodeEncodeErrors when sending emails
Log UnicodeEncodeErrors when sending emails

Summary: It should help us debug this weird production error.

Test Plan: This is just an exception handler.

Reviewers: emfree

Reviewed By: emfree

Differential Revision: https://phab.nylas.com/D1923

nylas/sync-engine,Eagles2F/sync-engine,Eagles2F/sync-engine,Eagles2F/sync-engine,ErinCall/sync-engine,jobscore/sync-engine,gale320/sync-engine,gale320/sync-engine,ErinCall/sync-engine,jobscore/sync-engine,nylas/sync-engine,closeio/nylas,gale320/sync-engine,Eagles2F/sync-engine,closeio/nylas,gale320/sync-engine,ErinCall/sync-engine,jobscore/sync-engine,closeio/nylas,jobscore/sync-engine,closeio/nylas,ErinCall/sync-engine,Eagles2F/sync-engine,gale320/sync-engine,ErinCall/sync-engine,nylas/sync-engine,nylas/sync-engine