fix: fixed-navbar-at-top

ISSUE #420

fixes #420

The Ad-bar should be below the appbar. So, altered it.

This was the Issue^

Checklist

[X] My code follows the code style of this project.
[ ] My change requires a change to the documentation.
[ ] I have updated the documentation accordingly.
[X] All new and existing tests passed.
[X] The title of my pull request is a short description of the requested changes.

Provide a Deployed link of route/page that needs to review Preview: Deploy preview link here with the appropriate route

Cannot provide the deployed preview since the project is not starting in local-server

codeforcauseorg / edu-client