Currently, when collection metadata is imported from table:_mdb_catalog, we did not fill the tenant id for its ns NamespaceString field. Refer to the code of wiredtiger_import.cpp.  

In this ticket, we will change the code to parse the tenant and db name from
rawCatalogEntry's "ns" and create the correct ns NamespaceString field with them.  Also, we will change the existing codes which access the "CollectionImportMetadata::ns" , for example tenant_file_importer_service.cpp.