Despite the "File Manager" being enabled in the "Feature Management" menu and working properly for the System tenant admins, the tenant admins receive the "Access Forbidden" error on the opening attempt:

Go to:
Admin -> Server & Hardware -> System Management -> Configuration (at the top right corner) -> 5 clicks on the Sisense logo to open extended configuration menu -> Api-Gateway -> Filebrowser
1. The "filebrowser.multiTenantPodsEnabled" toggle is enabled
2. The path in the "filebrowser.image" starts with "quay.io/sisense/file-browser"