Fix NUCAPS reader for NUCAPS EDR v2 files

[djhoese]

Problem description

NUCAPS EDR v2 files have changed the value of the instrument_name global attribute. Old:

            :platform_name = "NPP" ;
            :instrument_name = "CrIS" ;

New:

            :platform_name = "NPP" ;
            :instrument_name = "CrIS, ATMS, VIIRS" ;

This results in a comma-separated sensor instead of a list of sensors and when used in a filename results in commas in a filename...fun.

Expected Output

A list of sensors for the .attrs['sensor'] metadata value instead of a string with commas.