Dynamic attributes with entity type throw exception if entity in a secondary data store

[glebfox]

Case:

1. Create a dynamic attribute with entity type and entity class from a secondary data store
2. Add dynamic attribute to screens
3. Try to create an entity with dynamic attribute and fill its value
4. Save

AR:

Local Exception Stack: 
Exception [EclipseLink-0] (Eclipse Persistence Services - 2.7.9.6-jmix): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Problem compiling [select e from Customer e where e.id in :ids]. 
[14, 22] The abstract schema type 'Customer' is unknown.
[31, 35] The state field path 'e.id' cannot be resolved to a valid type.