[ci][python] apply isort to examples/python-guide/plot_example.py #3958 (#3963)
[ci][python] apply isort to examples/python-guide/plot_example.py #3958 (#3963)


microsoft/LightGBM,microsoft/LightGBM,henry0312/LightGBM,henry0312/LightGBM,microsoft/LightGBM,henry0312/LightGBM,henry0312/LightGBM,microsoft/LightGBM,microsoft/LightGBM,henry0312/LightGBM