fix(tasks) Notify when actions on threads fail
fix(tasks) Notify when actions on threads fail

Summary: It is better to notify that a task failed rather than having a thread or group of threads randomly bounce back.

Test Plan: manual

Reviewers: evan, spang, mark, halla

Reviewed By: mark, halla

Subscribers: mark

Differential Revision: https://phab.nylas.com/D3790

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