Remove gh setup from global proxy test

.github/workflows/__global-proxy.yml

@@ -48,18 +48,6 @@ jobs:
     timeout-minutes: 45
     runs-on: ${{ matrix.os }}
     steps:
-  # These steps are required to initialise the `gh` cli in a container that doesn't
-  # come pre-installed with it. The reason for that is that this is later
-  # needed by the `prepare-test` workflow to find the latest release of CodeQL.
-      - name: Set up GitHub CLI
-        run: |
-          apt update
-          apt install -y curl libreadline8 gnupg2 software-properties-common zstd
-          curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg
-          apt-key add /usr/share/keyrings/githubcli-archive-keyring.gpg
-          apt-add-repository https://cli.github.com/packages
-          apt install -y gh
-        env: {}
       - name: Check out repository
         uses: actions/checkout@v6
       - name: Prepare test