Catalog of tenant db views are stored in <tenantId><db>.system.views_ . It's a per-tenant collection.
The serialization/deserialization of "_id" field of it is a nss string of the view name. This field should always has tenant prefix as other general catalogs do. 

In the views_for_databse.cpp, there are bugs (eg, here) that didn't follow the above rule and use featureFlagRequireTenantID to decide if tenant prefix is included or not. We should fix it. Otherwise, server cannot reload the view catalog correctly if
feature flag is changed.