Fix problems in msr_sqa
It shows below when I run test:

FAILED tests/test_dataset_common.py::LocalDatasetTest::test_load_dataset_all_configs_msr_sqa - ValueError: Unknown split "validation". Should be one of ['train', 'test'].

It make no sense for me😂. 

The last version has many problems,

1) Errors in table load-in. Split by a single comma instead of using pandas is wrong.
2) id reduplicated in _generate_examples function.
3) Missing information of history questions which make it hard to use.

I fix it refer to https://github.com/HKUNLP/UnifiedSKG. And we test it to perform normally.