Split kafka writer tests into a consumer loop and an object check
This makes the consumer loop easier to reuse in other more specific tests
Test Plan
tox tests still pass
Migrated from D2961 (view on Phabricator)
Staging instance, all changes can be removed at any time
This makes the consumer loop easier to reuse in other more specific tests
tox tests still pass
Migrated from D2961 (view on Phabricator)