[tests][python-package] refactor list_to_1d_numpy test to run without pandas installed (#4639)
[tests][python-package] refactor list_to_1d_numpy test to run without pandas installed (#4639)

Co-authored-by: Nikita Titov <c256f4532c1890487c50410631b1b890b90daa3a@hotmail.com>
microsoft/LightGBM,microsoft/LightGBM,microsoft/LightGBM,henry0312/LightGBM,microsoft/LightGBM,henry0312/LightGBM,henry0312/LightGBM,henry0312/LightGBM,microsoft/LightGBM,henry0312/LightGBM