As we reported earlier Windows 10 Mobile People app picked Fluent Design elements with the last update. But with the latest update, Microsoft People app removes Fluent Design element.
The new people app version is 10.2.1921.0. We received this update on our phone enrolled to Fast Ring of Windows Insiders. It is not yet available on Release Preview or Production rings.
People app changelog:
Remove Fluent Design element.
Bug fixes and performance improvements
You can download the updated app from the link given below.