Split parquet schema mismatch
Part of https://github.com/huggingface/datasets-server/issues/1443
We have 11 cache records for split-first-rows-from-parquet because of ArrowInvalid when split parquets have a different schema.
See 
![Screenshot from 2023-11-16 15-02-48](https://github.com/huggingface/datasets-server/assets/5564745/020e300e-5830-46cb-9560-0aa88e1b5606)

This PR contains:
- Intercept ArrowInvalid exception when trying to concatenate shared parquet files in parquet_utils.py
- Separated tests from test_rows.py to test_response.py and test_parquet_utils.py since there was not a specific rows logic inside.
- Added a test in test_parquet_utils.py to simulate schema mismatch error.
Split parquet schema mismatch: Part of https://github.com/huggingface/datasets-server/issues/1443
We have 11 cache records for split-first-rows-from-parquet because of ArrowInvalid when split parquets have a different schema.
See 
![Screenshot from 2023-11-16 15-02-48](https://github.com/huggingface/datasets-server/assets/5564745/020e300e-5830-46cb-9560-0aa88e1b5606)

This PR contains:
- Intercept ArrowInvalid exception when trying to concatenate shared parquet files in parquet_utils.py
- Separated tests from test_rows.py to test_response.py and test_parquet_utils.py since there was not a specific rows logic inside.
- Added a test in test_parquet_utils.py to simulate schema mismatch error.