fix(navbar): show Dashboard instead of Classes label for admin users

[AbiramiR-27]

Checklist:

• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title

Closes #597

This PR dynamically renames the navbar link "Classes" to "Dashboard" for ADMIN users to match the actual destination page.

Changes:

• Added the custom session callback to NextAuth config to expose user roles to the client.
• Added a helper function in Navbar to recursively find and update the label for links to /classes based on user role.
• Added unit tests to navbar.test.jsx to cover both admin and teacher role scenarios.

[NewtonLC]

Hi @AbiramiR-27, thank you for working on this issue! I tested your code, and it works as expected. Before merging this though, I'd like to modify it to also hide this button if the user is not signed in, or if the user has a role other than ADMIN or TEACHER.

Would you be alright with adding those changes? If not, no worries! I can patch it later this week.

[AbiramiR-27]

Thank you for testing the changes and for the feedback! I'd be happy to make the additional updates. I'll modify the implementation to hide the button when the user is not signed in and when the user's role is neither ADMIN nor TEACHER, then update the PR shortly.

[NewtonLC]

Looks good to me! This PR is now awaiting a review from @utsab before merging.

[AbiramiR-27]

Hi @utsab, Gentle ping for a final review on this. @NewtonLC has approved it. Thank you!

[AbiramiR-27]

Hi @utsab @NewtonLC , just following up to see if you've had a chance to review this PR. In the meantime, I'll go ahead and resolve the merge conflicts in components/navbar.js. Thanks!

[NewtonLC]

Hi Abirami, I apologize for the wait. At the moment, we still aren't able to give a clear date for when we can review and merge your PRs. I still appreciate your work on both of them and will definitely reach out once we are able to review them.

[AbiramiR-27]

Hi @NewtonLC,
Thanks for the update! No worries at all. Just reach out whenever the team is ready to review.