rollback github action to python 3.13

- with python 3.14 the test often hangs

.github/workflows/python-app.yml

@@ -37,10 +37,10 @@ jobs:
     - uses: actions/checkout@v5
       with:
         fetch-depth: 0  # Shallow clones should be disabled for a better relevancy of analysis
-    - name: Set up Python 3.14
+    - name: Set up Python 3.13
       uses: actions/setup-python@v6
       with:
-        python-version: "3.14"
+        python-version: "3.13"
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip