CLDR-18026 fix for commit checker

- Update commit-checker.yml to call setup-python
- issue in actions/runner-images#10781

.github/workflows/commit-checker.yml

@@ -41,6 +41,9 @@ jobs:
           ref: ${{ github.event.inputs.tool-ref }}
           lfs: false # not needed here
           path: icu
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12' 
       - name: Run Check and Publish
         run: |
           echo "::group::Setup Checker"