PR checks: Remove code for unsupported versions

.github/workflows/__test-proxy.yml

@@ -50,11 +50,6 @@ jobs:
           apt-add-repository https://cli.github.com/packages
           apt install -y gh
         env: {}
-      - name: Setup Python on macOS
-        uses: actions/setup-python@v5
-        if: runner.os == 'macOS' && matrix.version == 'stable-v2.14.6'
-        with:
-          python-version: '3.11'
       - name: Check out repository
         uses: actions/checkout@v4
       - name: Prepare test