The CheckUserInsert service needs to support writing to the cuc_agent_id, cule_agent_id, and cupe_agent_id columns if the schema migration configuration value added in T361173: Add schema migration config for cu_useragent table indicates to write to these columns.
At the same time, support to not write to the cuc_agent, cule_agent, and cupe_agent columns needs to be added. This should be able to be done in the same change.
Acceptance criteria
- The CheckUserInsert service should support writing to the agent_id columns if SCHEMA_COMPAT_WRITE_NEW is set
- The CheckUserInsert service should only write to the agent columns if SCHEMA_COMPAT_WRITE_OLD is set