Add streamlit to CI

.github/workflows/python-tests.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --progress-bar off --upgrade pip setuptools
-          pip install boto3 moto[s3] pytest
+          pip install streamlit boto3 moto[s3] pytest
           pip install --progress-bar off .
           python -m pip install --progress-bar off --upgrade git+https://github.com/optuna/optuna.git
       - run: pytest python_tests