[Infrastructure] Update actions/upload-artifact to v4 (Resolves #2585) (#2587)

Author: angelosilvestre

.github/workflows/pr_validation.yaml

@@ -94,7 +94,7 @@ jobs:
       - run: flutter test test_goldens
 
       # Archive golden failures
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         if: failure()
         with:
           name: golden-failures
@@ -267,7 +267,7 @@ jobs:
       - run: flutter test test_goldens
 
       # Archive golden failures
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         if: failure()
         with:
           name: golden-failures