Update React and React Router dependencies and removed the portal related text (#56)

## Motivation
Update React and React Router dependencies and removed the portal
related text

## Proposal
- updated react to latest version
- removed the `When you've successfully solved the puzzle, return to the
Portal to claim your points.` text


## Test Plan
tested it manually
<img width="1720" height="1002" alt="image"
src="https://github.com/user-attachments/assets/bfba1526-14e3-4b09-bca6-e4b0c0e3b261"
/>

Author: TudorEsan

frontend/package.json

@@ -46,9 +46,9 @@
     "intl-messageformat": "10.7.16",
     "lucide-react": "^0.539.0",
     "next-themes": "0.4.6",
-    "react": "18.3.1",
-    "react-dom": "18.3.1",
-    "react-router-dom": "^6.30.0"
+    "react": "19.2.3",
+    "react-dom": "19.2.3",
+    "react-router-dom": "^7.10.1"
   },
   "devDependencies": {
     "@react-types/shared": "3.30.0",

frontend/src/components/puzzles/PuzzleTutorial.tsx

@@ -80,13 +80,6 @@ export function PuzzleTutorial() {
                   Submit when you've solved the puzzle to record it on the blockchain!
                 </p>
               </div>
-              <div className="flex gap-3">
-                <div className="h-4 w-4 bg-gray-300 flex-shrink-0" />
-                <p className="text-sm text-gray-500">
-                  When you've successfully solved the puzzle, return to the Portal to claim your
-                  points.
-                </p>
-              </div>
             </div>
           </div>
         </div>