Hydra Indexer pooled-executor bug

On one of the production QN machines, the Hydra indexer crashed with the following error.

```
022-09-21T21:40:01.791Z index-builder:indexer Done block #2616857
2022-09-21T21:50:01.755Z index-builder:pooled-executor Error getting next generator value
2022-09-21T21:50:01.756Z index-builder:pooled-executor Generator is done, exiting
2022-09-21T21:50:01.756Z index-builder:pooled-executor Generator is done, exiting
2022-09-21T21:50:01.756Z index-builder:pooled-executor Generator is done, exiting
2022-09-21T21:50:01.756Z index-builder:pooled-executor Generator is done, exiting
2022-09-21T21:50:01.756Z index-builder:indexer Index builder has been stopped
2022-09-21T21:50:01.756Z index-builder:redis-factory Closing Redis connections
2022-09-21T21:50:01.757Z index-builder:indexer Index builder has been stopped
error Command failed with exit code 255.
```

Though, the initial assessment is that this happened because the machine's recourses were exhausted since the indexer started working fine after the reboot. However, this issue needs further investigation