Normalize windows line endings in cohort csvs

When uploaded cohort csv files come from windows machines
they have the \r\n line endings.
These were normalized in a way that a blank line was inserted.
This fix prevents the blank line insertion.

Bug: 72581
Change-Id: I1f87b27bf667da76440929664da5b3c3ffa3d13e
Merge "Normalize windows line endings in cohort csvs"