## Description
In Postgres, localized blocks or arrays that contain other array / block
/ relationship fields were not properly storing locales in the database.
Now they are! Need to check a few things yet:
- Ensure test coverage is sufficient
- Test localized array, with non-localized array inside of it
- Test localized block with relationship field within it
- Ensure `_rels` table gets the `locale` column added if a single
non-localized relationship exists within a localized array / block
Fixes step 6 as identified in #7805
