Release Block all requests feature

What does this MR do and why?

This merge request removes the deny_all_requests_except_allowed feature flag to release the Block all requests feature #377371 (closed).

Documentation is being added in !113643 (merged).

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 #377371 (closed)