"Refactor AdminUser component from createReactClass to functional com…

[Yash121l]

What this PR does

This PR refactors the "AdminUser" component from createReactClass to a functional component. This will help towards aims to modernize the codebase and improve the performance and readability of the component.

Screenshots

Before:

https://github.com/WikiEducationFoundation/WikiEduDashboard/assets/98008765/afa973f0-a881-4165-9c7b-20629a08d5af

After:

https://github.com/WikiEducationFoundation/WikiEduDashboard/assets/98008765/d7ee62ca-7e2e-4d1b-a994-625bd83eb841

Open questions and concerns

• During the refactor, I ensured that the component's behavior remains the same. However, it would be great to have a thorough review to catch any potential edge cases I might have missed.
• I'm wondering if there are any additional hooks or patterns we should adopt to further enhance the functionality or performance of this component.