Support for the _Unsigned attribute?

[asinghvi17]

Describe the bug

Values read by NCDatasets and ZarrDatasets were inconsistent with xarray for this file, because it was interpreted as Int16 data but the attributes had an _Unsigned = true key, so the element type should have been UInt16 instead.

using AWSS3, FilePathsBase
download(p"s3://noaa-goes16/ABI-L2-SSTF/2020/210/00/OR_ABI-L2-SSTF-M6_G16_s20202100000205_e20202100059513_c20202100105456.nc", "noaa.nc")
using Rasters, NCDatasets
Raster("noaa.nc")
# or whichever other way you care to load it

You can see the debugging history in rafaqz/Rasters.jl#735

To Reproduce

Please provide a minimal julia code example which reproduces the behavior (bug, performance regression, ...).

Expected behavior

I would expect that the array is somehow reinterpreted to the appropriate unsigned type.

Environment

• operating system:Mac M1
• Julia version: 1.10
• CommonDataModel version: latest