CI: Remove Homebrew's setup-homebrew action

This was used to ensure that we had Python 3.12 or newer. The Ubuntu
24.04 runners now have Python 3.12, and the macOS 15 and 26 runners have
Python 3.14.

.github/actions/services-validator/action.yaml

@@ -44,16 +44,9 @@ runs:
     - name: Install and Configure Python 🐍
       shell: bash
       run: |
-        : Install and Configure Python 🐍
+        : Configure Python 🐍
         if [[ "${RUNNER_DEBUG}" ]]; then set -x; fi
 
-        echo ::group::Python Set Up
-        if [[ "${RUNNER_OS}" == Linux ]]; then
-          eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
-          echo "/home/linuxbrew/.linuxbrew/bin:/home/linuxbrew/.linuxbrew/sbin" >> $GITHUB_PATH
-          brew install --overwrite --quiet python3
-        fi
-
         python3 -m venv .venv
 
         source .venv/bin/activate

.github/workflows/scheduled.yaml

@@ -22,8 +22,6 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 0
-      - name: Set Up Homebrew 🍺
-        uses: Homebrew/actions/setup-homebrew@8eb7f2efa6ab636da09aef605b497fd5b8a7587d
       - name: Check for Defunct Services 📉
         uses: ./.github/actions/services-validator
         with: