Fix: Memory leak due to setState in unmounted components & redundant Navbar re-render on each route

Created by: abhishekakade

Description of PR

• Added a check and cleanup function in useEffect to avoid setting state in unmounted components.
• Will fix memory leak caused due to setting state in unmounted components.
• Removed Navbar from Suspense in App.js to prevent redundant Navbar re-renders on each route.

Relevant Issues
Closes #1763 (closed)

Checklist

• Compiles and passes lint tests
• Properly formatted
• Tested on desktop
• Tested on phone