Taxa deleted while still in use

[JimBacon]

If a taxon has a scientific name and a common name you can record against either one. Each name has a different taxa_taxon_list_id and so a record made against the common name will have the taxa_taxon_list_id of that name.

If the Warehouse UI is then used to modify the common name, the old taxa_taxon_list entry is marked deleted and a new one is added.

The consequence is that a record made against the original common name now has a reference to a taxon that no longer exists.

This was first noticed because it means the record is excluded from queries to add it to Elasticsearch.