Summary:
`ProducerSchemaPB producer_schema` was replaced with `SchemaVersionsPB schema_versions` as part of 066792c / D19791.

**Upgrade/Rollback safety:**
This is safe to do since the change has been backported to 2.16.1 (6deed15/D20533).
Due to the major ysql upgrade(Pg 11 -> Pg 15), direct upgrades to current version are not supported from older versions like 2.16.

Fixes #24901
Jira: DB-14029

Test Plan: Jenkins

Reviewers: slingam, xCluster

Reviewed By: slingam

Subscribers: ycdcxcluster, ybase

Differential Revision: https://phorge.dev.yugabyte.com/D39963