Parallel Replicas: Disabling with IN Subquery (Experimental Feature)

Why it matters

This feature addresses issues with parallel replicas executing queries containing IN subqueries by allowing users to disable parallel replicas in these specific cases, improving query correctness and performance consistency.

How to use it

Users can disable parallel replicas for queries with IN subqueries by enabling the experimental feature introduced in this update. Details on configuration are available in the linked pull request.