VIIRS SDR DNB units and file_units are conflicting

[TAlonglong]

Describe the bug

Missmatch between file_units and units for VIIRS SDR DNB
https://github.com/pytroll/satpy/blob/main/satpy/etc/readers/viirs_sdr.yaml#L464-L475

Don't know which is right.

Additional context
I user using the VIIRS SDR data is confused by the conflicting file_units and units.

These should be the same?

[djhoese]

Yes, they are different because the units are converted. The file_units are the units of the data in the file. The units are what you should get when you load it with Satpy. Sorry if I'm missing the question.

[TAlonglong]

Ah, ok. I expected them to be equal. Now I understand.

Thanks!