Change Tracker: changes of embedded value of reference entity are not properly tracked

[Gavrilov-Ivan]

Changes of embedded values are not provided by EntityChangedEvent. This leads to inability to find dependent entities to reindex.
See jmix-framework/jmix#211

Testing:

1. Create 2 entities with one-to-many association between them (root -> reference)
2. Reference entity should have embedded property
3. Create index definition for root entity what includes embedded property of reference entity
4. Create instances of root end reference entity (with filled embedded values). Link instances.
5. Process indexing queue
6. Make sure ES index contains document for created root entity
7. Update some embedded value in reference entity
8. Process indexing queue
9. Make sure ES document has been updated

[maistrenkoIulia]

verified