* WIP persons table schema migration
* add version to create_person
* test increased timeout
* Update ee/clickhouse/migrations/0019_person_table_version_column.py
* remove flaky kafka test
* format
* test a new approach - make this a non-large migration?
* Update ee/clickhouse/migrations/0021_person_table_version_column.py
* update
* events dead letter queue CH table
* format
* update schemas
* also store raw payload
* better naming
* make table name more clear
* wip better testing
* remove unused imports
* remove kafka test
* prevent non null test from running on CH migrations
* add kafka testing
* minor tests cleanup
* test naive longer sleep
* make test end-to-end
* address review
* update ttl, format
* refactor delay func, address review