Need to set the defaultIndex per tenant to `container-logs-*` to avoid errors switching tenants

[tobybellwood]

The default behaviour of Opensearch is to set the default index for a tenant to the first index discovered (here)

Defines the default index for all indexes in an OpenSearch cluster. If no indexes are added, defaultIndex is set to null. However, if one or more indexes are added, defaultIndex is assigned the value of the first index in the list. Default is null.

This causes issues switching between tenants whilst in "discover" mode because we've often created the index patterns before there is data in the indexes, which causes OpenSearch Dashboards to error as the default index doesn't have a timestamp field

[smlx]

I'm not convinced setting the defaultIndex option would fix this error message since they don't seem related: defaultIndex relates to indices, while the error message in your screenshot relates to index patterns and fields.

If you are still seeing this bug and are able to provide reproduction steps please let me know.