chore: update forum links in NavLinks (#39141)

client/src/components/Header/Header.test.js

@@ -23,7 +23,7 @@ describe('<NavLinks />', () => {
     return acc;
   }, []);
 
-  const expectedLinks = ['/learn', '/news', '/forum'];
+  const expectedLinks = ['/learn', '/news', 'https://forum.freecodecamp.org'];
 
   it('renders to the DOM', () => {
     expect(root).toBeTruthy();

client/src/components/Header/components/NavLinks.js

@@ -17,7 +17,11 @@ function NavLinks({ displayMenu }) {
           </Link>
         </li>
         <li className='nav-forum'>
-          <Link external={true} sameTab={true} to='/forum'>
+          <Link
+            external={true}
+            sameTab={true}
+            to='https://forum.freecodecamp.org'
+          >
             /forum
           </Link>
         </li>