Use allow_no_indices: true to avoid failures after manually deleted indices

If someone manually deletes an index via Kibana using `DELETE /my_index_rollover_2024-01`, we see failures from EG because it still attempts to search against the now-deleted indexes. Specifically, we see errors like `no such index [my_index_rollover_2024-01]`.

This is caused by EG caching the full list of indices and using that when it makes queries against OpenSearch.

From discussion, the solution would be to set `allow_no_indices: true` ([docs link](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-search-1)) to avoid these errors after indices are manually created.