Enable Group Level Security Policies in GraphQL API

What does this MR do and why?

With this MR we would like to unwrap backend part of &4425 (closed) and remove unneeded feature flag for it as we do not want to be able to present this feature to customers as a backend only feature without work needed on the frontend (scheduled for %15.2).

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #360995 (closed)