Move JSON, Dynamic, and Variant types to beta and backport fixes to 24.11

Why it matters

This change promotes these flexible and powerful data types out of the experimental phase and into beta, indicating increased stability and readiness for broader use. It solves the issue of limited trust and adoption by developers due to the experimental label, thereby encouraging more production use and providing greater confidence in their reliability.

How to use it

Users can start using the JSON, Dynamic, and Variant types in their schemas without requiring special experimental feature flags. These types are now available by default as beta features to facilitate easier integration and testing in production workloads.