Benchmarks silently execute stock version if scikit-learn-intelex is not installed

[michael-smirnov]

If I try to run benchmarks with the command like

python runner.py --configs configs/skl_xpu_config.json

it should run a patched version of scikit-learn algorithms. However, if scikit-learn-intelex package is not installed, benchmarks cannot be patched and should print an error or warning.

I cannot see the message in https://github.com/IntelPython/scikit-learn_bench/blob/master/bench.py#L204 for some reason.

[lulin789]

SKL_Bench_Team1 working on this issue