Use explicit node version 26 to match Dockerfile

Agent-Logs-Url: https://github.com/IntelliTect/EssentialCSharp.Web/sessions/fbba773e-6096-4a94-bbee-7b81246100f1

Co-authored-by: BenjaminMichaelis <22186029+BenjaminMichaelis@users.noreply.github.com>

Author: Copilot

.github/workflows/PR-Build-And-Test.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Set up Node.js
         uses: actions/setup-node@v4
         with:
-          node-version-file: EssentialCSharp.Web/package.json
+          node-version: '26'
           cache: npm
           cache-dependency-path: EssentialCSharp.Web/package-lock.json