Exclude sent messages from thread-level folder moves.
Exclude sent messages from thread-level folder moves.

Fixes T3345.

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