[Bug] Some unlikely workflow task failures like failure conversion issues may be lost

[cretz]

Describe the bug

When reviewing the reworking of #492, we can have errors in the lambda/task passed to QueueNewTaskAsync of the StartChildWorkflowAsync. So if an error on failure conversion occurs in there, we are not logging it because we are not logging/catching all errors for QueueNewTaskAsync.

This same thing could happen in other places where we are not properly catching errors in tasks passed to QueueNewTaskAsync. We need to be catching these and setting currentActivationException (and maybe add logging if the existing task failure logging is inadequate). Whether this is done in each QueueNewTaskAsync caller or at the general level can be decided by implementer.