Draft: Enable `webui_members_inherited_users` feature flag by default
What does this MR do and why?
Merged only after the feature flag has been enabled on production #364078.
MR acceptance checklist
Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
How to set up and validate locally
See !144638 (merged).
Related to #364078