* Docs: add hidden_users configuration field

* Add feature in the what's new

* Update configuration.md

* apply PR feedback

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* fix what's new link

* Update docs/sources/whatsnew/whats-new-in-v7-4.md

Co-authored-by: Leonard Gram <leo@xlson.com>

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
Co-authored-by: Leonard Gram <leo@xlson.com>