Stop installing already installed ninja

Author: mmcgr

.github/workflows/Guidelines.yml

@@ -48,8 +48,6 @@ jobs:
       uses: actions/checkout@v7
       with:
         fetch-depth: 2
-    - name: Install ninja-build tool
-      uses: seanmiddleditch/gha-setup-ninja@v6
     - name: Install dependencies
       run: sudo sh/setup/install_ubuntu_deps.sh
     - name: generate with Ninja