ci: upgrade e2e.yaml actions to Node.js 24-compatible versions

Update action versions ahead of GitHub's June 2, 2026 Node.js 20 deprecation:

- actions/setup-node@v4 → @v6
- actions/upload-artifact@v4 → @v7

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.github/workflows/e2e.yaml

@@ -24,7 +24,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: '22'
           cache: 'npm'
@@ -64,7 +64,7 @@ jobs:
         run: scripts/teardown-e2e-headlamp.sh
 
       - name: Upload Playwright report
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         if: failure()
         with:
           name: playwright-report
@@ -72,7 +72,7 @@ jobs:
           retention-days: 7
 
       - name: Upload test results
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         if: failure()
         with:
           name: test-results