[ENH] Empty rows in the middle of the dataset are erroneously accepted

[fabianegli]

The test for empty rows is probably good enough if these rows are at the beginning or end of the file, but it is not sufficient for the case when there are empty rows in the middle, because that could also be a hint that the file content does not comply with SDRF standards or contains more parts than only the SDRF.

https://github.com/bigbio/sdrf-pipelines/blob/837af51f360e81d5b9b6b10a21698fc4c7a3c582/sdrf_pipelines/sdrf/sdrf.py#L36-L38