Prevent an error when fetching a task that was never assigned to a
worker.
The error:
```
WRN error fetching task worker
error="fetching worker : worker not found: sql: no rows in result set"
```
Prevent an error when fetching a task that was never assigned to a
worker.
The error:
```
WRN error fetching task worker
error="fetching worker : worker not found: sql: no rows in result set"
```