R1:737e7c85412c

When an in-process worker subtask fails permanently, don't fatal the whole process

Summary:
Ref T13552. Fixes T13569. Currently, if a process uses in-process tasks (usually, a debugging/diagnostic workflow) and those tasks (or tasks those tasks queue) fail permanently, the exception escapes to top level and the process exits.

This isn't desirable; catch the exception and fail them locally instead.

Test Plan:
With a failing Asana integration and misconfigured Webhook, ran `bin/repository reparse…