ci: fix unsupported uv cache in setup-python action

Remove cache: 'uv' parameter as it's not supported by actions/setup-python@v5.
The action itself fails with 'Caching for uv is not supported' error.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/test.yml

@@ -18,7 +18,6 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: '3.11'
-          cache: 'uv'
 
       - name: Install uv
         run: |